ci: enforce the checks the contributor rules already required

Four gates that were documented but unenforced, plus the flaky test that
made a full-suite run untrustworthy.

Rust lint/format: CLAUDE.md has required `cargo fmt` and `cargo clippy`
before every commit for as long as the rule existed, yet neither ran
anywhere in CI — the requirement rested on memory alone. Both now run in
build-and-test.yml and build-release.yml. rustfmt and clippy are already
baked into the builder image, so nothing is installed at job time.
`cargo fmt --all -- --check` is strict immediately (the tree is clean).
Clippy is advisory for now: ~51 pre-existing warnings mean `-D warnings`
would fail on unrelated work, so the step carries a TODO to flip the flag
once the backlog clears. A compile error still fails it, so it is not a
no-op.

Traceability threshold: MIN_THRESHOLD sat at 50 while real coverage was
86%, so nearly half the matrix could rot before the gate objected.
Ratcheted to 82 with the policy written down — it only ever goes up, and
is never lowered to make a red build pass. The same figure lives in
MIN_COVERAGE_PERCENT so `traces:coverage` gates locally on the same bar,
and a test fails if the two drift.

Dangling IDs: a TRACES comment could name any well-formed ID and the
extractor accepted it silently, so typos and renames that missed a call
site passed unnoticed. `bun run traces:validate` cross-checks every
traced ID against the table rows in requirements.md and fails with the
referencing files listed. It spans UT/IT as well, which the coverage
orphan list ignores by design. This currently reports DR-189 and UT-188,
which are being defined separately.

Flaky offlineCatalog test: the first dynamic import of the service paid
~1s to transform its dependency graph, charged to a test body against
vitest's 5s default. Alone it passed; under suite-wide contention it
timed out. The import is now warmed at collection time, so no test is
timing the compiler — the timeout is deliberately unchanged. The store
shim also drops subscribers from module instances discarded by
resetModules, which previously leaked across tests.

.gitea/workflows/traceability-check.yml

@@ -81,8 +81,20 @@ jobs:
             exit 1
           fi
 
-          # Check minimum threshold
-          MIN_THRESHOLD=50
+          # Minimum coverage. RATCHET POLICY: this number only ever goes UP.
+          #
+          # It sits a few points under the coverage actually achieved, so a real
+          # regression trips it. It was 50 while true coverage was 86%, which
+          # meant nearly half the matrix could rot before CI said a word — a
+          # gate that cannot fail is not a gate.
+          #
+          # When coverage rises durably, raise this to just under the new figure
+          # (`bun run traces:coverage` prints it). Never lower it to make a red
+          # build pass — add the missing TRACES comments instead.
+          #
+          # Keep in sync with MIN_COVERAGE_PERCENT in scripts/extract-traces.ts;
+          # scripts/extract-traces.test.ts fails if the two drift apart.
+          MIN_THRESHOLD=82
           if [ "$COVERAGE" -lt "$MIN_THRESHOLD" ]; then
             echo "❌ ERROR: Coverage ($COVERAGE%) is below minimum threshold ($MIN_THRESHOLD%)"
             exit 1
@@ -90,6 +102,15 @@ jobs:
 
           echo "✅ Coverage is acceptable ($COVERAGE% >= $MIN_THRESHOLD%)"
 
+      # Every ID named by a TRACES comment must be defined as a table row in
+      # docs/requirements.md. The extractor used to accept any well-formed ID
+      # silently, so a typo or a rename that missed a call site passed CI
+      # unnoticed (DR-189 and UT-188 lived in three source files, defined
+      # nowhere, for months). This covers UT/IT too, which the coverage
+      # orphan list above deliberately ignores.
+      - name: Validate requirement IDs
+        run: bun run traces:validate
+
       - name: Check modified files
         if: github.event_name == 'pull_request'
         run: |