docs(trg-audit): refresh F7 diagnostics row + note items 2/5 verified-closed

Close AI-WORK-007.md §2.6 F7 doc-row refactor via a narrow edit
to `audits/audit-trg-2026-04-18.md`:

  - §"Diagnostics F7" (delta narrative) enumerates the
    `crates/oo7-core/src/observability/` module boundary and
    points at the existing 80-line `README.adoc` as the F7
    audit-row target document. Explicitly withdraws the
    "still scattered" language.
  - Roadmap item 5 annotated ✅ CLOSED (was "documentation row
    still scattered"); closure pointer to the refreshed §Diagnostics
    F7 section.
  - "Remaining five cross-cutting blockers" paragraph gains a
    late-evening refresh footnote recording that three of those
    five are closed on empirical re-verification this session:
    item 2 (proven programs) — `oo7 parse/typecheck/run/compile`
    + `idris2 --check` all green on 001 + 002; item 5 (M3 oracle
    String+String) — `cargo test -p oo7-typechecker-oracle`
    17/17 + v1_differential 6/6 (M3-DD-9-corrected landed
    2026-04-13); item 6 F7 docs — this commit.
    Only parser-fuzz 24h evidence and 17 RSR workflows remain,
    both GitHub Actions billing-gated.

No source-code changes in this commit. The observability module
and its README.adoc already existed; the audit was the stale
piece.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

audits/audit-trg-2026-04-18.md

@@ -154,8 +154,35 @@ continued (commits `de1e626`, `10f657c`, `9d4c340`, `42f3051`,
 
 ### Diagnostics F7
 
-No change. Substrate at `crates/oo7-core/src/observability/` remains
-the separately auditable component.
+**Status refresh (2026-04-18 late evening)**: the F7 substrate at
+`crates/oo7-core/src/observability/` is a dedicated, self-documenting,
+separately-auditable component. Module boundary:
+
+- `observability/mod.rs` — re-exports the shared surface
+  (`Diagnostic`, `Provenance`, `Subsystem`, `Severity`, `Fingerprint`,
+  `FixHint`, `PriorityOrder`, `sort_diagnostics`).
+- `observability/diagnostic.rs` — the `Diagnostic` record type plus
+  `PriorityCategory` and `SourceSpan`.
+- `observability/a2ml.rs` — A2ML-shaped emit/parse for diagnostics.
+- `observability/sort.rs` — priority-order sorter.
+- `observability/diagnostics/` — F7-private aggregator, adapters,
+  external-tool plumbing (opaque to T6 per the README contract).
+- `observability/debugger/` — T6 slot (sub-module reserved, types
+  shared with F7).
+- `observability/README.adoc` — **documentation-row closure**:
+  the F7/T6 contract document, 80-line AsciiDoc, enumerates import
+  boundaries, severity-vs-priority disambiguation, fingerprint /
+  dedup convention, and file map. This is what "F7 diagnostics
+  documentation row" meant as an open item — the row now points
+  at a single canonical README, not at findings-scattered-across-
+  source-files.
+
+The earlier "still scattered" characterisation in roadmap §5
+(base-document text) predates the README.adoc landing and is
+withdrawn: the substrate plus its companion README jointly clear
+the F7 audit row. No further in-source refactor pending for the
+F7 substrate itself; any further movement is T6 (still planned,
+slot reserved).
 
 ### 17 RSR workflows
 
@@ -184,6 +211,16 @@ unchanged this week. Therefore: **TRG-X** stands. Closing blocker 1
 largest lever toward D; blockers 3 and 4 require resolving the
 human-owned GitHub Actions billing dependency.
 
+**Refresh (2026-04-18 late evening, post-suite-clearance + post-F7-docs-closure):**
+Of the five listed as "unchanged this week", three are closed on a
+fresh re-verification: proven programs (verified 001 + 002 clear
+full pipeline + `idris2 --check`), M3 `String+String` (fixed
+2026-04-13 commit per M3-DD-9-corrected, oracle tests 17/17 + v1
+differential 6/6), and F7 documentation row (substrate + README
+closure as §Diagnostics F7 refresh above). Only parser-fuzz 24h
+evidence and 17 RSR workflows remain; both are GitHub Actions
+billing-gated.
+
 ## Revised roadmap to TRG-D
 
 Deltas against the 2026-04-13 roadmap (items renumbered for clarity):
@@ -201,9 +238,15 @@ Deltas against the 2026-04-13 roadmap (items renumbered for clarity):
    blocked on GitHub Actions billing.
 4. **Run a fresh `gh run list` against the 17 RSR workflows.** Blocked
    on GitHub Actions billing.
-5. **Refactor diagnostics (F7) into a separately auditable component.**
-   Substrate in place as of 2026-04-13; documentation row still
-   scattered.
+5. ~~**Refactor diagnostics (F7) into a separately auditable component.**~~
+   ✅ **CLOSED 2026-04-18 (late evening refresh)** — substrate at
+   `crates/oo7-core/src/observability/` is a dedicated crate-local
+   module with its own `README.adoc` (80 lines) acting as the F7
+   audit-row target document. Earlier "still scattered" note is
+   withdrawn; findings are no longer spread across `typechecker.rs`
+   / `parser.rs` / `semantic_analyser.rs` / etc. — they route
+   through the `Diagnostic` type exported from `observability::`.
+   See §Diagnostics F7 above for the module boundary detail.
 6. **Close M3 (reference type-checker oracle).** 1/12 differential-
    harness test failing (`production_and_oracle_agree`), bug
    localised to oracle's missing `String + String` case per