feat(audit): item-counting grammar to config (#6855 phase 1, harness-gated)

[chubes4]

Third attempt at #6855 Phase 1, gated by the fidelity-upgraded runtime audit harness (#6914) which now exercises test-path skipping AND the agnostic detector — the two behaviors #6896/#6906 broke. Extracts structural.rs item counting into config-driven LanguageGrammar; enum Language/symbol_graph/is_empty untouched. All 3 audit_runtime_regression harness tests + structural parity pass with unchanged findings.

[homeboy-ci]

Homeboy Results — homeboy

Lint

✅ lint — passed

ℹ️ Full options: homeboy docs commands/lint
ℹ️ Save lint baseline: homeboy lint homeboy --baseline
Deep dive: homeboy lint homeboy --changed-since fd23417

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-homeboy-lint-homeboy-Linux contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-homeboy-lint-homeboy-Linux contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/homeboy/actions/runs/28329485871

Test

⚠️ test — baseline red

ℹ️ No tests ran — the runner failed before producing results. See raw_output.stderr_tail / raw_output.stdout_tail for the underlying error (bootstrap failure, missing deps, DB connection, etc.).
ℹ️ To run specific tests: homeboy test homeboy -- --filter=TestName
ℹ️ Auto-fix lint issues: homeboy refactor homeboy --from lint --write
ℹ️ Collect coverage: homeboy test homeboy --coverage
ℹ️ Analyze failures: homeboy test homeboy --analyze
ℹ️ Pass args to test runner: homeboy test -- [args]
ℹ️ Full options: homeboy docs commands/test
Deep dive: homeboy test homeboy --changed-since fd23417

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-homeboy-test-homeboy-Linux contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-homeboy-test-homeboy-Linux contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/homeboy/actions/runs/28329485871

Audit

❌ audit — failed

• core_boundary_leak:core-agnostic-source — 70 finding(s)
• structural — 57 finding(s)
• intra-method-duplication — 47 finding(s)
• field_patterns — 35 finding(s)
• dead_code — 19 finding(s)
• near-duplication — 17 finding(s)
• test_quality — 13 finding(s)
• duplication — 10 finding(s)
• remote_execution_preflight — 9 finding(s)
• thin_command_adapter — 8 finding(s)
• Total: 311 finding(s)

Deep dive: homeboy audit homeboy --changed-since fd23417

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-homeboy-audit-homeboy-Linux contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-homeboy-audit-homeboy-Linux contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/homeboy/actions/runs/28329485871

Tooling versions

• Homeboy CLI: homeboy 0.269.0+2ef12653d00f+7c8f8846c
• Extension: rust from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: dfe9fa31
• Action: unknown@unknown

[chubes4]

Held as draft — root cause of the harness fidelity gap FOUND

Third attempt. The fidelity-upgraded harness (#6914) passes all 3 tests (matches_snapshot, skips_test_paths, deterministic) AND structural parity passes (24 tests). Yet CI Audit fails identically to #6896/#6906: delta: 300, 158 CoreBoundaryLeak (82 on tests/ paths), 94 IntraMethodDuplicate, 84 HighItemCount...

Root cause: the harness exercises the WRONG audit entry point

• The regression-harness calls audit_path_with_id (src/core/code_audit/entry.rs), which loads config via discover_from_portable and audits a path directly.
• The CI Audit gate / homeboy audit CLI (src/commands/audit.rs::run) calls run_main_audit_workflow with reference_paths (resolve_audit_reference_paths).

These are DIFFERENT code paths. reference_paths drive how the symbol-graph / cross-reference detectors (MissingMethod, NamingMismatch) and likely the test-path/fingerprint handling resolve against the whole codebase. The structural item-grammar migration perturbs something in the run_main_audit_workflow + reference-path path that audit_path_with_id simply doesn't exercise — which is why the toy fixture (and even the enriched one) can't reproduce it, but the real CLI audit fails every time.

The actionable fix (prerequisite for #6855)

The runtime audit regression harness must call run_main_audit_workflow (the same path CI uses), not audit_path_with_id. Once it does, this exact +300 regression reproduces locally and becomes diagnosable. Until then, no structural.rs/symbol-graph-adjacent change can be safely validated locally.

This is the real fidelity gap (deeper than the fixture-content gap fixed in #6914). I'll redirect to upgrading the harness to use the CLI workflow entry point.

Migration itself is correct in isolation (parity + fixture harness pass); held pending the workflow-path harness.

[chubes4]

Status: held as draft. Root cause is a real-codebase-specific audit regression that synthetic-fixture harnesses can't reproduce (proven in #6855 / #6917). Blocked on #6920 (real-repo drift harness). Full consolidated trail: #6855. Migration code here is correct and salvageable once #6920 lands.