feat(#1740): require-fs-op-fallback production AST rule + Windows transient-lock retry (Phase 6) (#1742)

* feat(#1740): require-fs-op-fallback production AST rule + Windows transient-lock retry (Phase 6)

ADR-1703 Phase 6 of the cross-platform portability epic (#1702). Adds the
second production-code portability AST rule + the ADR-mandated glob expansion
to bin/install.js and scripts/build-hooks.js.

- eslint-rules/require-fs-op-fallback.cjs: flags an unguarded fs.rename /
  fs.renameSync (the atomic-publish primitive named first in
  DEFECT.WINDOWS-FS-OPS.symptom) that is NOT inside a try/catch whose handler
  references a transient errno ('EPERM'/'EBUSY'/'EACCES' or a *RETRY_ERRNOS
  set) AND NOT behind a Windows platform guard. A catch that silently swallows
  or cleans-up-and-rethrows without an errno check does NOT satisfy the
  defect's 'never silently swallow' clause. copyFile/unlink are deliberately
  not flagged (they are the fallback primitives per the defect's own
  fix-forward). Scope narrowed to rename per Phase 5's precision discipline;
  documented on #1740.

- src/shell-command-projection.cts: export retryRenameSync(from, to) — the
  drop-in bounded-retry helper over the existing atomicRenameWithRetry.

- 27 bare fs.renameSync sites across 11 modules routed through retryRenameSync
  (capability-lifecycle/lock/source, installer-migrations, milestone, phase,
  planning-workspace, roadmap-upgrade, runtime-hooks-surface, state,
  workstream). Idempotent on POSIX; resilient to AV/indexer transient locks
  on Windows.

- eslint.config.mjs: register rule at error on src/**/*.cts; new focused
  portability-rules block covering bin/install.js + scripts/build-hooks.js
  (ADR-1703 L124-126 glob expansion — both files are compliant: zero
  rename violations).

- tests: 15-case RuleTester suite; portability-rule-disable-ban extended
  (PROTECTED_RULES + scans bin/install.js/build-hooks.js with shebang
  handling); ci-test-scope portability-lint selection rule.

- CONTEXT.md DEFECT.WINDOWS-FS-OPS predicate rewritten to point at the rule;
  docs/contributing/cross-platform-portability-rules.md reference + how-to.

Closes #1740

* chore(#1740): backfill changeset pr:1742

* fix(#1740): tighten require-fs-op-fallback precision (codex review HIGH-1/HIGH-2)

Addresses two false-negative findings from the codex (gpt-5.5/high)
adversarial review of PR #1742:

HIGH-1 — a catch that REFERENCES a transient errno but only rethrows (no
retry/fallback) was marked compliant. The DEFECT.WINDOWS-FS-OPS fix-forward
requires retry, not just recognition. Fix: catchHandlerHasRetrySignal now
requires a loop `continue` backedge OR a `return <call>` delegation; a bare
rethrow is flagged. The misleading `/* retry logic */` valid test is replaced
with a real retry loop, and the rethrow-only shape is added as invalid.

HIGH-2 — the nested-try ancestor walk treated an OUTER errno-catch as
protecting the rename even when an INNER catch intercepted/swallowed the error
(the outer catch is unreachable). Fix: isInsideTransientErrnoTryCatch now stops
at the NEAREST enclosing TryStatement WITH A CATCH HANDLER whose block contains
the rename (try-finally is skipped — it doesn't catch); outer catches are no
longer consulted. The unsound nested-try valid test is converted to invalid,
and a try-finally-skipped valid case is added.

Verified: 17 RuleTester cases pass; zero new production violations (the 27
fixed sites use retryRenameSync; the real retry loops — atomicRenameWithRetry,
capability-ledger/consent, build-hooks — remain compliant via continue/errno);
lint:ci green; disable-ban + vocab-drift green.

---------

Co-authored-by: review-bot <review-bot@gsd>

src/workstream.cts

@@ -23,7 +23,7 @@ const { toPosixPath, generateSlugInternal } = coreUtils;
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import roadmapParser = require('./roadmap-parser.cjs');
 const { getMilestoneInfo } = roadmapParser;
-import { platformWriteSync, platformEnsureDir } from './shell-command-projection.cjs';
+import { platformWriteSync, platformEnsureDir, retryRenameSync } from './shell-command-projection.cjs';
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import planningWorkspace = require('./planning-workspace.cjs');
 const { planningRoot, setActiveWorkstream, getActiveWorkstream } = planningWorkspace;
@@ -92,13 +92,13 @@ function migrateToWorkstreams(cwd: string, workstreamName: string): MigrateResul
       const src = path.join(baseDir, item.name);
       if (fs.existsSync(src)) {
         const dest = path.join(wsDir, item.name);
-        fs.renameSync(src, dest);
+        retryRenameSync(src, dest);
         filesMoved.push(item.name);
       }
     }
   } catch (err) {
     for (const name of filesMoved) {
-      try { fs.renameSync(path.join(wsDir, name), path.join(baseDir, name)); } catch { /* ignore */ }
+      try { retryRenameSync(path.join(wsDir, name), path.join(baseDir, name)); } catch { /* ignore */ }
     }
     try { fs.rmSync(wsDir, { recursive: true }); } catch { /* ignore */ }
     try { fs.rmdirSync(path.join(baseDir, 'workstreams')); } catch { /* ignore */ }
@@ -310,12 +310,12 @@ function cmdWorkstreamComplete(cwd: string, name: string | null | undefined, opt
   try {
     const entries = fs.readdirSync(wsDir, { withFileTypes: true });
     for (const entry of entries) {
-      fs.renameSync(path.join(wsDir, entry.name), path.join(archivePath, entry.name));
+      retryRenameSync(path.join(wsDir, entry.name), path.join(archivePath, entry.name));
       filesMoved.push(entry.name);
     }
   } catch (err) {
     for (const fname of filesMoved) {
-      try { fs.renameSync(path.join(archivePath, fname), path.join(wsDir, fname)); } catch { /* ignore */ }
+      try { retryRenameSync(path.join(archivePath, fname), path.join(wsDir, fname)); } catch { /* ignore */ }
     }
     try { fs.rmSync(archivePath, { recursive: true }); } catch { /* ignore */ }
     if (active === name) setActiveWorkstream(cwd, name!);