VFS Federation Studio — Engineering Handoff after v0.0.8 P2

Continue development from VFS Federation Studio v0.0.8 P2 — Worker-Backed Rule Lab + Path Resolution Lens. Do not restart, redesign, or replace the existing preservation-first architecture. Preserve all passing functionality and advance it incrementally with executable evidence.

CURRENT VERIFIED FOUNDATION

v0.0.8 preserves the complete v0.0.7 P1 foundation: deterministic Federation Image v2 images, exact indexes, bounded embedded VFS views, recursive federation, preservation-first writable generations, generated pure-Perl runtime products, process-isolation architecture, authenticated IPC foundations, profile-v1 compatibility, profile-v2 federation-scoped Monk with strict boundary permissions, the headless Rule Lab contract, and the i18n/message-ID foundation.

Monk remains a policy/routing layer around normal federation ownership resolution, not a replacement index. Exact lookup remains the normal hot path. READ exact hits resolve before FALLBACK policy. WRITE policy may execute in PRE phase before ownership resolution. Profile-v2 rewrites/routes fail closed across ownership/mount boundaries unless cross_mounts is explicitly granted.

P2 now adds a deterministic, headless Path Resolution Lens report model. PathLensRequest/PathLensStep/PathLensReport consume production V2FederationRuntime resolution traces plus MonkEngine diagnostics and execution. The Lens can prove exact READ precedence, inspect eligible/missed rules, explain fallback rewrites/routes, show source/output ownership transitions, and represent typed policy errors such as VFS_E_MONK_BOUNDARY. WRITE Lens evaluation resolves routing/ownership but intentionally does not perform the write, so inspection is non-mutating.

MonkEngine.inspect_rules() now provides deterministic eligibility diagnostics without applying or rewriting policy. It reuses the runtime's actual eligibility logic and reports stable statuses for disabled, phase mismatch, operation mismatch, path/owner scope mismatch, context error, eligible regex miss and eligible match. Existing execution semantics remain the source of truth.

The Rule Lab request/report contract is now serializable for IPC. Rule fixtures can either carry explicit synthetic context or obtain real runtime ownership context from the opened VFS. The GUI does not evaluate regex or create a parallel Monk model.

Two supervisor/worker task kinds are now part of the protocol: RUN_RULE_LAB and TRACE_PATH_RESOLUTION. Workers load the V2 image, run the headless contracts, check cooperative cancellation boundaries and return JSON-safe reports. The GUI process presents results and correlates task IDs to the correct instrument; it does not load/evaluate policy for these operations.

The Studio UI source now contains graphical Rule Lab and Path Resolution Lens dock instruments. They use application-owned Monk/Lens/Run SVG iconography and emit worker requests rather than invoking MonkEngine or V2FederationRuntime. Their new user-facing strings use stable MessageId values from first implementation. Existing untranslated legacy surfaces may continue incremental migration, but new P2 surfaces do not introduce a second localization mechanism.

The P2 Lens intentionally supports READ and WRITE only. STAT/LIST/SEARCH are not visualized as executable Monk semantics until those operations are first wired to production runtime policy. Do not manufacture hypothetical traces merely to expand the UI.

No translation catalog for the requested four Asian languages/scripts is claimed. The exact four languages/scripts still require confirmation and later qualification. Display locale remains presentation-only and must not alter canonical .vfsbin bytes, fingerprints, mount behavior, Monk semantics or generated runtime behavior unless localized payload content is deliberately configured.

Generated Perl runtime behavior remains unchanged by P2 diagnostic/UI work. Python/Perl policy parity established by P1 remains a release gate, and generated Perl packages remain independently operational writable runtime products.

EXECUTABLE EVIDENCE FOR THIS CUT

Repository Python suite: 118 passed, 2 skipped in the assembly environment. The two skips are PySide6 runtime/platform tests because PySide6 is not installed; they are not GUI passes.

Generated-runtime Perl suites: 73 assertions PASS across five test files.

P2 Rule Lab + Path Resolution Lens proof: PASS. It exercises direct headless reports and spawned SupervisorService workers; proves exact READ precedence, real cross-mount fallback, strict WRITE boundary denial, real-runtime Rule Lab ownership context, and byte-for-byte preservation of the input .vfsbin after both instrument tasks.

Recorded P2 proof values for this source cut:
- Monk profile SHA-256: 49704df0b42c191de73cd1e0b70762b04a5349518a1e306d38549e1b4998be9c
- root image SHA-256: 5ee9b8a5e802e3a32104e07b33fc22232b16f602e8104e0960415bbf2a627727
- fallback Lens steps: 11
- denied-boundary Lens steps: 6

The P1 Monk-scope/i18n proof and preserved P0 vertical, writable-Perl and Monk proofs remain PASS. See docs/architecture/P2_EVIDENCE.md for commands and recorded values. Final release acceptance still requires these gates from a clean extraction of the packaged archive.

ENVIRONMENT-LIMITED QUALIFICATION

PySide6 is not installed in the assembly environment. The P2 Qt source surfaces have architecture/static regression coverage, custom SVG validation and syntax/import-boundary checks, but their actual runtime layout, focus/keyboard behavior, accessibility tree, high-DPI/text-expansion behavior, platform window chrome and live docking interactions have not been exercised here. Do not describe those items as passed until they are run in a compatible PySide6 host environment.

PRESERVATION REQUIREMENTS

Never weaken the preservation-first model to make a feature easier. Authoritative sources remain read-only. Committed .vfsbin images are immutable generations. Mutations produce candidates, candidates are independently verified, and only the controlled commit path may promote them. Worker failure or cancellation cannot corrupt the last known-good destination. Embedded children remain bounded complete images.

Keep exact lookup out of regex policy scans. Monk eligibility/inspection may explain the policy path, but it must not replace exact indexes or make ordinary exact reads pay a global regex-scan cost.

Keep the GUI as a presentation/controller boundary. Substantial VFS open/build/write/rebuild/search/hash/verify/export/policy-evaluation work belongs in supervisor/workers. Preserve truthful progress and cancellation. Current worker isolation protects the GUI from long fixture/lens tasks, but cooperative cancellation does not preempt a single pathological regex call; that remains an explicit hardening item.

Keep Python reference behavior and generated Perl behavior in parity. A class/file existing is not proof of completion. Add regression tests for every material defect or contract extension. Test final packaged artifacts from a clean extraction. Distinguish environment-unavailable tests from actual passes.

Preserve the custom frameless Studio contract, custom Open/Save and secondary dialogs, application-owned SVG iconography, dark engineering-instrument visual language, and message-ID localization architecture. Do not regress to native/default Qt dialogs, QMessageBox, QFileDialog or OS/default icons for ordinary product UI.

Do not claim bounded-memory behavior for P2 instrument image loading: workers currently read the selected image bytes in the worker process. Large-package bounded-memory instrumentation remains future work.

IMMEDIATE NEXT DEVELOPMENT — P3

The strongest next increment is to expand executable Monk capability before adding corresponding UI claims.

1. Define named search-profile contracts in Monk profile v2 and wire real SEARCH behavior through the production runtime. Preserve exact-index fast paths and use regex/search policy only where selected by the operation/profile.
2. Define validation-policy contracts in Monk profile v2 and provide typed deterministic validation reports. Add Python fixtures and generated-Perl parity evidence before exposing authoring UI as complete.
3. Wire real STAT/LIST/SEARCH Monk semantics before extending Path Resolution Lens to those operations. The Lens must visualize production behavior, never a UI-only simulation.
4. Expand Rule Lab into multi-fixture authoring, persistence/history and project integration. Keep test fixtures outside canonical VFS identity unless the project deliberately embeds/configures them as semantic content.
5. Harden regex resource controls. Worker isolation is necessary but not sufficient for pathological patterns; add a well-defined evaluation/time budget or safely preemptible execution strategy and prove loop/application/trace/resource limits.
6. Add richer worker stage/progress reporting if search/validation workloads become long-running, preserving cooperative cancellation and typed failure states.
7. Run P2 Rule Lab/Lens in a real PySide6 host and qualify frameless/dock behavior, focus/keyboard use, accessibility text, high-DPI/text expansion and locale retranslation. Keep any unavailable platform cases explicitly separate.
8. Continue i18n catalog work only after the exact four target Asian languages/scripts are confirmed. Do not state a supported-language matrix before catalogs, font fallback, layout, input/search and generated-documentation behavior are tested.
9. Preserve writable generated Perl VFS capabilities, federation ownership/routing, deterministic image identity, preservation-first commits, exact lookup and clean-extraction release evidence throughout P3.

END PRODUCT CONTRACT

VFS Federation Studio is an engineering environment for creating a distinct, writable, programmable, federated virtual filesystem; exporting it as an independently operational Perl package; and proving exactly how that filesystem resolves, routes, searches, mutates, verifies and applies policy.
