fix(#1857): test gates normalize to one-shot + bounded timeout (no watch-mode hang)

A GSD verification gate resolves a project's test command and runs it. vitest
defaults to WATCH mode in an interactive TTY — exactly where a user runs
`gsd-execute-phase` — so a resolved `npm test`/`pnpm test` backed by vitest never
exited and the orchestrator waited indefinitely. Recovery needed the user to
manually prompt "something blocking?".

Fix — one shared helper + a bounded, surfacing timeout on the test-command gates:
- New pure module src/normalize-test-command.cts + `gsd-tools query
  normalize-test-command` verb: rewrites a resolved command to a best-effort
  one-shot form (direct vitest → `vitest run`; jest `--watch` → `--watchAll=false`;
  a package-manager `test` script whose package.json runner is watch-vitest →
  `CI=true` prefix; handles `--dir`; already-one-shot commands unchanged —
  never double-flagged). Named `normalize-test-command` (not `test-*`) so the
  file does not match node --test's default `test-*` discovery glob.
- The three gates that HUNG or silently-continued route through that ONE helper
  and bound execution with `timeout $(config-get workflow.test_gate_timeout)`
  (new config key, default 600s): the regression gate (extracted to
  execute-phase/steps/regression-gate.md since execute-phase.md is size-frozen —
  it shrank 93528→93132; ABORTS on exit 124), the post-merge gate, and the
  audit-fix gate (previously an UNBOUNDED `eval`). All name watch/dev mode on 124.
- verify-phase's gate was ALREADY bounded (a fixed `timeout 300`, not a hang), so
  it only gains the normalizer (so a watch runner exits fast) + a watch-mode hint
  on 124, staying under its frozen 40960-byte tier cap.

Security hardening (review): the normalizer only rewrites a runner named as a
standalone command TOKEN (so `run-vitest.js`/`make test-vitest`/paths are never
mangled), is length-capped and uses only linear-time split-based scanning (no
super-linear backtracking on an adversarial `workflow.test_command`), and reads
package.json only when it is a regular file (never blocks on a FIFO via `--dir`).

Config key `workflow.test_gate_timeout` (seconds, default 600) registered in the
schema manifest + templates/config.json + docs/CONFIGURATION.md (mirrors
workflow.cross_ai_timeout). New module registered in .gitignore, eslint ignores,
inventory manifest/index. All 16 golden-install-parity fixtures + workflow size
baseline regenerated for the changed shipped files; bin/lib is excluded from the
parity manifest.

Tests: tests/normalize-test-command.test.cjs (normalizer units incl. security
hardening) and tests/test-gate-watch-mode.test.cjs (the three core gates route
through the shared helper + configured timeout + exit-124 watch-mode hint;
verify-phase asserted as normalize-only/already-bounded).
tests/execute-phase-active-flags.test.cjs repointed at the extracted step;
tests/planner-language-regression.test.cjs allowlist comment updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.changeset/1857-test-gate-watch-mode-timeout.md

@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 2060
+---
+**Test gates can no longer hang forever on a watch-mode test runner.** vitest defaults to watch mode in an interactive terminal (exactly where `gsd-execute-phase` runs), so a resolved `npm test` / `pnpm test` that maps to vitest never exited and the orchestrator waited indefinitely until the user manually intervened. Every GSD test-command gate — the regression gate, the post-merge gate, the audit-fix gate, and the verify-phase gate — now routes the resolved command through a shared `normalize-test-command` helper that rewrites it to a one-shot form (direct vitest → `vitest run`; jest `--watch` → `--watchAll=false`; a package-manager `test` script backed by watch-vitest → `CI=true` prefix; already-one-shot commands are left unchanged). The three gates that previously hung or silently continued — the regression, post-merge, and audit-fix gates — additionally bound execution with a configurable `workflow.test_gate_timeout` (default 600s), aborting or surfacing the cause on timeout instead of hanging; the verify-phase gate was already bounded (a fixed 5-minute limit) and keeps it, now naming watch mode on timeout. The normalizer only rewrites a runner named as a standalone command token (so paths/targets like `run-vitest.js` are never mangled), is length-capped and linear-time on adversarial input, and only reads a regular-file `package.json`.