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>

CONTEXT.md

@@ -711,8 +711,8 @@ The prompt-level data/instruction isolation seam for untrusted web/document ingr
 
 `DEFECT.WINDOWS-FS-OPS.symptom=fs.renameSync / fs.copyFileSync hits EPERM/EBUSY on Windows when antivirus or another process holds a transient handle on the target`
 `DEFECT.WINDOWS-FS-OPS.examples=c47c2c5d build-hooks rename → copy fallback, d2412271 install Windows persistent SDK shim`
-`DEFECT.WINDOWS-FS-OPS.detect=any rename/copy in build/install path without try/catch fallback`
-`DEFECT.WINDOWS-FS-OPS.fix-forward=catch EPERM/EBUSY/EACCES, fall back to copy + unlink with retry, surface degraded-mode message; never silently swallow`
+`DEFECT.WINDOWS-FS-OPS.detect=ADR-1703 Phase 6: enforced by local/require-fs-op-fallback (AST ESLint rule, error) over src/**/*.cts + bin/install.js + scripts/build-hooks.js — flags an unguarded fs.rename/fs.renameSync (the atomic-publish primitive named in .symptom) that lacks a transient-errno retry or a Windows platform guard; a catch that silently swallows or cleans-up-and-rethrows without an errno check does NOT satisfy the .fix-forward clause. copyFile/unlink are the fallback primitives (out of scope); delegated retry helpers (retryRenameSync from shell-command-projection) are the recognized compliant shape`
+`DEFECT.WINDOWS-FS-OPS.fix-forward=catch EPERM/EBUSY/EACCES, fall back to copy + unlink with retry, surface degraded-mode message; never silently swallow; the canonical production cure is retryRenameSync (shell-command-projection.cjs) or a bounded RENAME_RETRY_ERRNOS = new Set(['EPERM','EBUSY','EACCES']) loop`
 
 `DEFECT.UNBOUNDED-SUBPROCESS.symptom=git/npm subprocess shelled out without timeout; CLI hangs indefinitely on stuck remote, large repo, or missing network`
 `DEFECT.UNBOUNDED-SUBPROCESS.examples=a33cbe72 worktree fix bound git subprocesses with timeout`