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.

CLAUDE.md

@@ -101,14 +101,22 @@ Tooling:
 bun run traces            # extract traces (default format)
 bun run traces:json       # JSON — e.g. | jq '.byType' or '.requirements."UR-005"'
 bun run traces:markdown   # regenerate docs/traceability.md
+bun run traces:coverage   # coverage gate — exits non-zero below the threshold
+bun run traces:validate   # dangling-ID gate — every traced ID must be defined
 git diff --name-only | xargs grep -L "TRACES:"   # find untraced changed files
 ```
 
+Every ID a `TRACES:` comment names must exist as a table row in
+`docs/requirements.md` — `traces:validate` fails otherwise, so a typo or a
+rename that missed a call site can no longer pass silently.
+
 **CI is Gitea Actions** (`.gitea/workflows/`, remote `gitea.tourolle.paris`), not
 GitHub. `traceability-check.yml` fails the build if coverage drops below
-**50%** (`MIN_THRESHOLD`); `build-and-test.yml` runs frontend + Rust tests and an
-Android `cargo check`. See [docs/traceability-ci.md](docs/traceability-ci.md) and
-[docs/traces-quick-ref.md](docs/traces-quick-ref.md).
+**82%** (`MIN_THRESHOLD`, a *ratchet* — raise it as coverage climbs, never lower
+it to make a build pass) or if any traced ID is undefined; `build-and-test.yml`
+runs frontend + Rust tests, `cargo fmt --check`, an advisory `cargo clippy`, and
+an Android `cargo check`. See [docs/traceability-ci.md](docs/traceability-ci.md)
+and [docs/traces-quick-ref.md](docs/traces-quick-ref.md).
 
 ### Traces drive release notes