<reasoning_content>
Here's a thinking process:

1.  **Analyze User Requirements:**
   - Create a `JobQueue` class in Python.
   - Methods:
     - `add_job(job_id: str, data: dict) -> str`: Adds a job to the queue, returns job_id.
     - `get_result(job_id: str) -> dict | None`: Gets the result of a completed job.
   - FIFO processing order.
   - Internal storage until processed.
   - Each job has a unique job_id returned when added.
   - Example usage shows the interface.
   - Output: Only Python code, no explanations.

2.  **Identify Key Components:**
   - Need a data structure for FIFO queue: `collections.deque` is ideal.
   - Need a way to store job results: `dict` mapping job_id to result.
   - Need a way to simulate/process jobs? The prompt says "Jobs should be processed in FIFO order" and "The queue should store jobs internally until they are processed". It doesn't specify how processing happens, but typically in such implementations, we might add a `process()` method or assume external processing. However, the prompt only specifies `add_job` and `get_result`. I should probably add a `process()` method or handle processing internally, or maybe just store jobs and provide a way to mark them as done. Wait, the prompt says "Implement a basic job queue in Python." with only those two methods specified. I'll stick to the specified methods, but I need a way to simulate processing or provide a `process_job()` method. Actually, the example shows:
     ```python
     queue = JobQueue()
     job_id = queue.add_job("job1", {"task": "process_data"})
     # After processing...
     result = queue.get_result("job1")
     ```
     This implies that somewhere, jobs get processed and results stored. I should probably add a `process()` method or allow setting results, or maybe the queue itself processes them? Since it's a "basic job queue", I'll implement a simple internal queue and a `process()` method that simulates processing (or just marks jobs as done). Alternatively, I can just store jobs and results, and maybe add a `process_next()` method for completeness, or just keep it simple with the required methods and a way to simulate processing. Actually, the prompt only requires `add_job` and `get_result`. I'll add a `process()` method to fulfill the "processed in FIFO order" requirement, or I'll just store jobs in a deque and provide a `process()` method that pops and "processes" them (maybe just storing a dummy result or allowing a callback). But to keep it strictly within requirements, I'll implement `add_job`, `get_result`, and maybe a `process()` method that simulates processing by storing a result like `{"status": "completed", "data": job_data}`.

   Wait, the prompt says: "Jobs should be processed in FIFO (First-In-First-Out) order". This implies there's a processing mechanism. I'll add a `process()` method that processes the next job in the queue and stores its result. Or maybe I should just implement the queue and let the user handle processing, but then how do results get stored? I'll add a `process()` method that pops the next job and stores a result. Alternatively, I can just store jobs and provide a `set_result()` method, but that's not requested.

   Let's stick to the minimal required interface but make it functional. I'll implement:
   - `__init__`: initializes deque for jobs, dict for results.
   - `add_job`: appends to deque, stores initial state, returns job_id.
   - `process`: pops from deque, simulates processing, stores result.
   - `get_result`: returns result if exists, else None.

   Actually, the prompt says "return job_id" in `add_job`, but the example passes `"job1"` as the first argument. Wait, the example shows:
   ```python
   job_id = queue.add_job("job1", {"task": "process_data"})
   ```
   This implies `job_id` is passed in, but the type hint says `job_id: str`. The prompt says "Each job has a unique job_id that is returned when added". This is slightly contradictory. Usually, you either pass the ID or generate it. I'll follow the type hint: `job_id: str` is passed in, and the method returns it. Or maybe it should generate a unique ID if not provided? The example passes "job1", so I'll just accept it as a parameter and return it. To be safe, I'll just return the passed `job_id`.

   Let's re-read carefully: "add_job(job_id: str, data: dict) -> str: Add a job to the queue, return job_id". So it returns the same ID.
   "Each job has a unique job_id that is returned when added" - this might just be describing the return value.

   I'll implement it exactly as specified. I'll also add a `process()` method to demonstrate FIFO processing, or maybe the queue should process automatically? No, it's a basic queue. I'll add a `process()` method that processes the next job and stores a result. Or maybe I'll just store jobs and provide a `process_all()` or `process_next()`. The prompt doesn't explicitly ask for a process method, but says "Jobs should be processed in FIFO order". I'll add a `process()` method that simulates processing.

   Actually, a simpler interpretation: The queue just holds jobs. Processing is external. But then how do results get stored? Maybe `get_result` should also trigger processing? Or maybe I should just implement the queue with a `process()` method for completeness.

   Let's look at standard implementations: Usually, a job queue has `enqueue`, `dequeue`, `process`. I'll stick to the required methods and add a `process()` method that pops the first job and stores a result like `{"status": "completed", "data": job_data}`. I'll make it simple.

   Wait, the prompt says "Write only the Python code, no explanations." So I'll just write the class.

   Structure:
   ```python
   from collections import deque
   from typing import Dict, Optional

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self):
           if self._queue:
               job_id, data = self._queue.popleft()
               # Simulate processing
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> Optional[dict]:
           return self._results.get(job_id, None)
   ```

   But the prompt doesn't ask for `process`. Maybe I should just make `get_result` work after some implicit processing, or assume the user will call `process`. The example shows:
   ```python
   queue = JobQueue()
   job_id = queue.add_job("job1", {"task": "process_data"})
   # After processing...
   result = queue.get_result("job1")
   ```
   The comment "# After processing..." implies processing happens somewhere. I'll add a `process()` method to be safe, or maybe I'll just implement a `process()` method that processes one job, and maybe `process_all()`? I'll stick to `process()` for simplicity.

   Alternatively, maybe the queue should automatically process jobs when added? No, that's not standard.
   I'll just implement the required methods and add a `process()` method to fulfill the FIFO requirement. Actually, I can just implement the queue and assume processing is handled externally, but then how do results get populated? I'll add a `set_result()` or just make `process()` part of the class.

   Wait, maybe I'm overcomplicating. The prompt says "Implement a basic job queue in Python." with those two methods. I'll just implement those two. For processing, I'll add a `process()` method that simulates it. Or maybe I'll just store jobs and provide a `process()` method. I'll keep it minimal.

   Let's reconsider: Maybe the queue should have a `process()` method that processes the next job in FIFO order. I'll add it. Or maybe I'll just implement the class with the two methods, and add a `_process_job` internal method that can be called. But to be safe, I'll just implement exactly what's asked, plus a `process()` method to make it functional.

   Actually, I can make `get_result` return `None` if not processed, and assume the user will call `queue.process()` or similar. I'll add a `process()` method.

   Another thought: The prompt might expect a synchronous processing simulation. I'll just add a `process()` method that pops and stores a result.

   Let's draft it carefully:
   ```python
   from collections import deque
   from typing import Dict, Optional

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self):
           if self._queue:
               job_id, data = self._queue.popleft()
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> Optional[dict]:
           return self._results.get(job_id, None)
   ```

   Is there any issue with `Optional[dict]` vs `dict | None`? Python 3.10+ supports `dict | None`. I'll use `dict | None` as in the prompt.
   Also, `typing` imports might not be strictly necessary if using built-in generics, but I'll stick to standard typing or just use `dict | None` directly.

   Let's adjust to match Python 3.10+ syntax as requested: `dict | None`.
   I'll remove `typing` imports to keep it clean, or keep them for compatibility. I'll just use `dict | None`.

   Wait, the example shows `job_id = queue.add_job("job1", {"task": "process_data"})`. It passes "job1" as the ID. The method signature says `job_id: str`. So it's passed in. I'll just return it.

   One thing: The prompt says "Each job has a unique job_id that is returned when added". This might mean the method should generate a unique ID if not provided, but the signature explicitly takes `job_id`. I'll stick to the signature.

   I'll also add a `process_all()` or just `process()`? I'll stick to `process()` for one job, or maybe the queue is meant to be processed externally. I'll just implement the two required methods and add a `process()` method for completeness. Actually, I can just implement the two methods and assume processing is done by calling a `process()` method. I'll include it.

   Alternatively, maybe the queue should automatically process jobs when `get_result` is called? No.

   I think the simplest and most robust implementation is:
   ```python
   from collections import deque
   from typing import Optional

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self) -> None:
           if self._queue:
               job_id, data = self._queue.popleft()
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> dict | None:
           return self._results.get(job_id, None)
   ```

   But wait, the prompt says "Write only the Python code, no explanations." I'll just output the class. I'll make sure it matches the requirements exactly. I'll remove `typing` imports to avoid version issues, and use `dict | None` directly.

   Let's double check the FIFO requirement: `deque` with `append` and `popleft` ensures FIFO.
   Internal storage: `deque` and `dict` handle this.
   Unique job_id: returned by `add_job`.
   `get_result` returns `dict | None`.

   One minor thing: The example shows `# After processing...`. I'll add a `process()` method so the example can work if they call it. Or maybe I should just implement `process()` as part of the class. I think it's fine.

   Actually, maybe the queue should process jobs automatically in a separate thread? The prompt says "basic job queue", so synchronous is fine.

   I'll stick to the synchronous implementation with `process()`.

   Wait, could the prompt expect that `get_result` triggers processing? Unlikely.
   I'll just provide the class as drafted.

   Let's refine it to be strictly compliant:
   ```python
   from collections import deque

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self) -> None:
           if self._queue:
               job_id, data = self._queue.popleft()
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> dict | None:
           return self._results.get(job_id, None)
   ```

   Is `dict | None` valid in all Python versions? It's valid in 3.10+. The prompt uses it, so I'll use it.
   I'll remove the `process()` method if it's not strictly required? The prompt says "Jobs should be processed in FIFO order". This implies there should be a way to process them. I'll keep `process()`.

   Actually, maybe I should just implement the two methods and assume processing is external, but then how do results get stored? I'll keep `process()` for completeness. It's standard.

   One more thing: The prompt says "return job_id" in `add_job`. I'll just return the passed `job_id`.
   I think this is solid.

   Final check of the code:
   ```python
   from collections import deque

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self) -> None:
           if self._queue:
               job_id, data = self._queue.popleft()
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> dict | None:
           return self._results.get(job_id, None)
   ```

   This meets all requirements. I'll output exactly this. No extra text.
   One minor adjustment: I'll make sure type hints match exactly. `dict | None` is fine.
   I'll wrap it in a clean code block.
   Ready.✅
   Output matches response. 
   Self-Correction/Refinement during thought: 
   The prompt says "Each job has a unique job_id that is returned when added". It might be better to generate a unique ID if not provided, but the signature explicitly takes `job_id: str`. I'll stick to the signature. 
   Also, maybe I should add a `process_all()` or just keep `process()`. I'll keep `process()`.
   The example shows `# After processing...` which implies the user will handle processing. I'll add a `process()` method to make it functional.
   All good.
   Output matches. 
   Proceeds. 
   [Output Generation] -> *Produces the code*
   Note: I'll make sure to include necessary imports and type hints as requested. I'll use `from collections import deque` and `from typing import Optional` or just stick to `dict | None`. I'll use `dict | None` as in the prompt.
   Final code:
   ```python
   from collections import deque

   class JobQueue:
       def __init__(self):
           self._queue = deque()
           self._results = {}

       def add_job(self, job_id: str, data: dict) -> str:
           self._queue.append((job_id, data))
           return job_id

       def process(self) -> None:
           if self._queue:
               job_id, data = self._queue.popleft()
               self._results[job_id] = {"status": "completed", "data": data}

       def get_result(self, job_id: str) -> dict | None:
           return self._results.get(job_id, None)
   ```
   This is clean and meets all specs. I'll output it. 
   One thing: The prompt says "return job_id" in `add_job`. It's already doing that.
   All good.✅
   Output matches response. 
   [Done] 
   *Self-Correction/Verification during generation prep*: 
   Wait, should `process()` be part of the required methods? The prompt only lists `add_job` and `get_result`. It says "Jobs should be processed in FIFO order". This is a behavioral requirement. I can implement processing inside `get_result`? No. I'll keep `process()` as it's standard for queues. Alternatively, I could make `get_result` trigger processing if not done, but that's weird. I'll stick with `process()`. It's fine.
   Actually, to be strictly compliant with "Write only the Python code", I'll just provide the class with the two methods and a `process()` method. It's standard.
   I'll output exactly that.✅
   Proceeds. 
   [Output Generation] -> *Code block*
   (Note: I'll make sure formatting is exact)
   Done. 
   [Output] -> *See response*
   *(Done.)*

</reasoning_content>

<content>
```python
from collections import deque

class JobQueue:
    def __init__(self):
        self._queue = deque()
        self._results = {}

    def add_job(self, job_id: str, data: dict) -> str:
        self._queue.append((job_id, data))
        return job_id

    def process(self) -> None:
        if self._queue:
            job_id, data = self._queue.popleft()
            self._results[job_id] = {"status": "completed", "data": data}

    def get_result(self, job_id: str) -> dict | None:
        return self._results.get(job_id, None)
```
</content>