### expert_build/cli.py:main
VERDICT: PASS
CORRECTNESS: VALID
SPEC_COMPLIANCE: N/A
ISSUE_COMPLIANCE: N/A
BELIEF_COMPLIANCE: N/A
TEST_COVERAGE: UNTESTED
INTEGRATION: WIRED
REASONING: This change implements a proactive registration check to ensure the `argparse` subparser configuration and the `commands` dispatch dictionary remain synchronized. By performing a set comparison of the keys, it identifies both missing handlers (subcommands without dispatch) and dead code (dispatch keys without subcommands). This is a sound defensive programming practice that will catch developer errors immediately upon execution rather than waiting for a specific command to be invoked. The logic correctly handles the error reporting to `stderr` and terminates the process with a non-zero exit code if a mismatch is found. 
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### SELF_REVIEW
LIMITATIONS: I was able to see the full body of the `main` function via the observation results, which allowed me to confirm that the `commands` dictionary and the `sub` object (argparse subparser) were in scope and correctly defined. No specific test cases for CLI registration were provided, so the change remains technically untested, though its correctness is verifiable through static analysis of the `argparse` API usage.
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### FEATURE_REQUESTS
- Provide the content of `GEMINI.md` or other instruction files automatically if they contain architectural invariants or testing requirements.
- Show a list of all subcommands currently defined in the file to help verify the set comparison logic against the actual registration code.
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