enhance(#3883): route every slug call site through its canonical owner (#3896)

* docs(#3883): correct section 8.3 against the tree

I wrote this section in Phase 0 stating rules I had not executed against the
tree. Measured at 832dcbb75, three statements are wrong.

The slug count is 11 across 5 files, not 13; two of the thirteen were an
unrelated tokenizer regex. The divergence is real and reproduced.

resolveRuntime reads no install marker at all and has no cache; PR #3382,
cited as prior art for that rung, is closed unmerged.

The Codex sandbox is still a hand-maintained subset map with a silent
read-only fallback, and validate agents checks file presence only -- both
halves of that claim are false.

The shortFormToId rule is accurate. The guard roster names no casualty for
this rule.

Section 8.3 is therefore a work list, not a conformance check.

Refs #3883

* test(#3883): failing-first rows for slug re-implementation divergence

Refs #3883

* feat(#3883): route every slug call site through its canonical owner

Migrated commands.cts:209, init.cts:176/1935/1957/3109, phase-id.cts:229/380, phase-locator.cts:269, workstream-name-policy.cts:75 to generateSlugInternal (core-utils.cts:107).

Declared different: gsd2-import.cts:97 (no truncation), active-workstream-store.cts:97 (fixed ASCII env-key domain, already matches).

Fixed a latent circular-require bug: core-utils.cts top-level destructured comparePhaseNum/scopeToPhase from phase-id.cjs; switched both sides of the new circular require to lazy function-body requires.

Refs #3883

* fix(#3883): restore per-site truncation contracts broken by the slug consolidation

Refs #3883

* fix(#3883): close review findings — changeset, miscounts, loose rows, cyclic destructure

Refs #3883

* docs(#3883): correct the same slug miscount in the Context table

Section 8.3's rule text was corrected to 11 copies across 7 files; the Context
table above it still carried the original 13 across 5. Same wrong claim, second
location, both mine.

Refs #3883

* chore(#3883): backfill changeset PR number

Refs #3883

* test(#3883): keep the core-utils mutation shard inside its time budget

PR #3896's Stryker (core-utils) shard was cancelled at the 15-minute
shard cap. Stryker's command-runner bills one `node --test <file>`
invocation as a single unit costing whatever the file's slowest run
costs, re-run once per mutant (documented in
tests/state-contract.test.cjs's header, #2790 precedent). A3/A5 drove
every CLI-reachable slug site through runGsdTools (a real child-process
spawn per call, ~85-170ms each across ~70 calls), accounting for ~7.1s
of the file's ~7.9s wall time.

commands.cts:cmdGenerateSlug and init.cts:cmdInitExecutePhase/
cmdInitPhaseOp/cmdInitProgress are plain functions reachable in-process
from the built gsd-core/bin/lib/*.cjs, so this calls them directly
instead of spawning gsd-tools, capturing their fd-1 JSON output with the
bug #1008 fs.writeSync-mock pattern already used in tests/io.test.cjs
and tests/init.test.cjs. A hermetic-env helper reproduces the isolation
runGsdTools's { HOME: tmpDir } + testEnvBase() gave the child process.

File wall time drops from ~7.97s to ~1.1s (246/246 passing, same
coverage), well inside the 15-minute cap even at hundreds of mutants.

Refs #3883

---------

Co-authored-by: sim <sim@local>

src/active-workstream-store.cts

@@ -91,6 +91,14 @@ function getControllingTtyToken(): string | null {
 }
 
 function getWorkstreamSessionKey(): string | null {
+  // #3883 (ADR-3473 §8.3): DECLARED DIFFERENT from generateSlugInternal
+  // (core-utils.cts), the canonical slug formula — deliberately, not a
+  // consolidation gap. The text slugified here is never caller-supplied: it
+  // is always one of the fixed ASCII WORKSTREAM_SESSION_ENV_KEYS identifier
+  // names above (e.g. "GSD_SESSION_KEY"), which already agree with the
+  // canonical's output byte-for-byte on this restricted input domain (no
+  // unicode, no length anywhere near the 60-char truncation boundary) — so
+  // delegating would add a require() edge for zero behavioral change.
   for (const envKey of WORKSTREAM_SESSION_ENV_KEYS) {
     const raw = process.env[envKey];
     const token = sanitizeWorkstreamSessionToken(raw);