fix(cursor): emit preToolUse allow JSON under failClosed (2.5.66)

[szsunyuan]

Fixes #743

Summary

Cursor IDE blocks every tool call on the AI-DLC Cursor harness because
preToolUse is failClosed: true and the adapter allow path returns
exit 0 with empty stdout. Empty stdout is invalid JSON; the IDE denies.
Cursor CLI (agent) treats the same silence as allow, so #661's
CLI-only live verification missed this.

Changes

• harness/cursor/hooks/aidlc-cursor-adapter.ts guards: write
  {"permission":"allow"} on both allow returns (Task spawn and
  post-guard loop). Deny JSON and failClosed: true are unchanged.
• t276 asserts allow stdout is that JSON on captured guards allow
  paths; deny / malformed input still deny.
• docs/guide/harnesses/cursor.md documents the allow|deny JSON
  contract (empty stdout is an IDE deny).
• Regenerated dist/ via bun scripts/package.ts (not hand-edited).
• Version 2.5.66 (README badge + CHANGELOG). #731 already claimed
  2.5.65.

User experience

Before: Cursor IDE: Hook "bun .cursor/hooks/aidlc-cursor-adapter.ts guards" returned no output on every tool. CLI: tools run.

After: IDE and CLI both allow when the guards allow. Deny still
blocks with {"permission":"deny","agent_message":...}.

Upgrade: refresh dist/cursor/ and rerun
bun dist/cursor/install.ts /path/to/project.

Checklist

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Test Plan

• bun scripts/package.ts --check
• bun test tests/unit/t276-cursor-adapter.test.ts
• bun test tests/unit/t68-version-changelog-sync.test.ts
• bun tests/run-tests.ts --smoke --unit (t276/t68 green; t248 and
  t255 failed in isolation on this machine and are untouched by this
  diff)
• Live Cursor IDE 3.15.6: installed dist/cursor/ into
  /tmp/aidlc-cursor-verify; Read of AGENTS.md was allowed;
  bun .cursor/tools/aidlc-state.ts approve was denied by the
  state-transition guard

Acknowledgment

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of the
project license.

[leandrodamascena]

Approved at 3561e6c7. I rebased the branch onto the latest v2, preserved the existing release entries, rebumped this fix to 2.5.69, and regenerated all seven distribution trees.

The implementation correctly emits {"permission":"allow"} on every successful Cursor preToolUse guard path while preserving fail-closed denial behavior. Package parity, typecheck, and the focused adapter/version suites all pass (33/33). The PR is now mergeable; we're waiting for CI.