Closes Plan 1.5.1 §3 item #4 (the explicitly-deferred AST adapter output piping).

Closes Plan 1.5.1 §3 item #4 (the explicitly-deferred AST adapter output piping). Pre-1.5.4 introspectAsync() handed AST adapters SourceFile[] = [] because of a placeholder at codebase-introspector.ts:160-170. Adapters always worked (verified by adapter-grammar-strict.test.ts 10/10 fixtures with 'high' confidence) but their extracted conventions never reached the user-facing emitted config. 1.5.4 ships the real per-adapter file sampler and pipes AST output into detected.<adapter-id>: blocks.

Daemon code unchanged — 1.5.0 48 h soak verdict applies to 1.5.4.

Added

• detect/adapters/file-sampler.ts — per-adapter file sampler. Reuses EXTENSIONS and TEST_FILE_PATTERNS from source-dir-detector.ts:84-104 (no parallel maps; CR-46 self-attest #3). Algorithm: per language in adapter.languages, walk source dirs from detection.sourceDirs[<lang>].source_dirs up to depth 3, filter by extension, exclude test files, cap per-adapter at 50 files, drop files > MAX_AST_FILE_BYTES (256 KB). Refuses symlinks and ignored dirs (node_modules, .git, dist, target, etc.).
• AST output piping in runInit — after variant template merge, runs introspectAsync(detection, projectRoot) and merges every adapter's output (where _confidence !== 'none') into config.detected[<adapter-id>]. Each block carries the adapter's extracted conventions (route_method, scope_prefix_base, controller_class, etc.) plus _provenance and _confidence per types.ts:114-130.
• --no-introspect CLI flag — bypasses the AST introspect step. Useful for fast sync init or when grammar download is undesirable. Default-on (introspect runs).
• sample-files-coverage.test.ts — 3 strict gates: every language declared by ANY of the 10 first-party adapters has both SAMPLE_EXTENSIONS and SAMPLE_TEST_FILE_PATTERNS entries; extension strings are well-formed (no leading dot). Future adapters targeting an uncovered language fail the build.
• init-end-to-end.test.ts extension — added detected.<adapter-id>: block assertion: when the AST adapter for a fixture's framework returns non-'none' confidence, the block must carry _confidence and at least one non-meta convention key. Lenient on grammar-load failure (CI offline) but strict on shape when present.

Verification

• npx tsc --noEmit: 0 errors
• npm test: 2086 source-level tests pass (+8 tarball-level skipped per MASSU_TARBALL_E2E gate)
• MASSU_TARBALL_E2E=1 npm test: tarball gate runs against the 1.5.4 build with the new sampler + introspect piping
• bash scripts/massu-pattern-scanner.sh: PASS
• bash scripts/massu-generalization-scanner.sh: PASS
• 1.5.1's init-end-to-end.test.ts still green (5/5) — variant template merge stays correct
• core-bundled-ids-drift.test.ts: green (added file-sampler.ts to ADAPTER_SUPPORT_FILES)

Closes

• Plan 1.5.1 §3 item #4 ("Pipe introspectAsync() output to detected.<adapter-id>: block in the emitted config") — explicitly deferred at 1.5.1 ship; closed here.

Phase 7 fixture verification (cited)