Merge origin/main (v1.64.1.0 code-smell wave) into test-evals-ci-speedup

Both sides shipped overlapping test-infra work in parallel; resolutions
compose intent rather than picking sides:

- free-tests.yml (both added): keep this branch's lane (canonical
  strict-parallel runner, secretless, plain runner, ~2min) over main's
  per-file-serial container loop (45min budget, hand-curated skip list,
  needs GITHUB_TOKEN); ported main's git safe.directory insight.
- Dockerfile.ci Bun install: main discovered the installer IGNORES the
  BUN_VERSION env var (the old form silently installed latest) — main's
  arg-form mechanism + this branch's 1.3.13 target.
- parity baseline: both sides rebased after hitting the same silent
  drift; adopted main's v1.64.1.0 union-normalized fixture and dropped
  this branch's interim v1.64.0.0 capture. carve-guards caps: main's
  tighter re-ratchets win (all four).
- touchfiles: kept this branch's three-file facade split; ported main's
  pure-data removals (dead sidebar-agent entries, spec judge entry,
  ship-idempotency) into touchfiles-data.ts.
- ship-idempotency SDK variant: main deliberately removed it as
  redundant with the real-PTY test; adopted — dropped this branch's
  rehomed copy and its periodic matrix row (the zombie-monolith deletion
  stands; coverage-audit + triage rehomes verified untouched by main).
- e2e-tier-alignment: taught the new parent-mapper hard check main's
  consolidated describeE2ETier()/e2eTierEnabled() self-gate shapes (the
  helper's header names this file as a required recognizer).
- browse/test/compare-board.test.ts: quarantined behind
  GSTACK_COMPARE_BOARD_TESTS=1 — all 16 tests fail identically on
  origin/main solo on dev machines (blame protocol receipts in-file);
  main's own CI lane skip-lists it. An always-red file would block every
  PR now that free-tests is a required check.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/test-free-shards.ts

@@ -129,13 +129,6 @@ const WINDOWS_FRAGILE_PATTERNS: Array<{ pattern: RegExp; reason: string }> = [
   // BROWSE_HEADLESS_SKIP=1 to skip the browser launch but still need a working
   // server, which they don't get on Windows.
   { pattern: /BROWSE_HEADLESS_SKIP|spawn\(\[['"]bun['"],\s*['"]run['"]/, reason: 'spawns the browse server subprocess (Bun-driven path is Windows-broken)' },
-  // Tests that read browse/src/sidebar-agent.ts — deleted in v1.14.0.0
-  // sidebar refactor (replaced by sidepanel-terminal.js). 10 security tests
-  // still reference it and fail on import. They've been broken on every
-  // platform since v1.14, but Bun on macOS/Linux reports the failure as a
-  // module-load error (exit 0) while Bun on Windows treats it as a hard
-  // fail (exit 1). Tracked as a follow-up: update or delete these tests.
-  { pattern: /sidebar-agent\.ts/, reason: 'reads deleted browse/src/sidebar-agent.ts (pre-existing breakage from v1.14.0.0 sidebar refactor)' },
 ];
 
 // Explicit known-Windows-incompatible test files that don't fit a regex