chore(gitignore): collapse codex-pair entries to single .codex-pair/ line (ADR-092) (#180)

ask-llm plugin v0.7.1 moved every codex-pair state artifact (marker,
log, cache, ignore globs, pause sentinel, inflight locks) under a single
.codex-pair/ directory per ADR-092. The old four-line gitignore block
(`.codex-pair-context.md`, `.codex-pair-log.jsonl`, `.codex-pair-cache/`,
`.codex-pair-state/`) no longer matches the layout — those exact paths
never get created by the new hook, so the entries are dead.

Replaced with a single `.codex-pair/` entry that covers every nested
artifact including any future additions the plugin adds.

Verified locally:
- migrated .codex-pair-context.md → .codex-pair/context.md
- migrated .codex-pair-log.jsonl → .codex-pair/log.jsonl
- migrated .codex-pair-cache/ → .codex-pair/cache/
- migrated .codex-pair-state/ → .codex-pair/state/
- the new hook fires on the next Edit (smoke test caught both planted
  issues: regex-injection HIGH + non-import-type MED in 19s)
- `git check-ignore` confirms all three .codex-pair/* paths covered by
  the single line

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: Lykhoyda

.gitignore

@@ -21,8 +21,8 @@ scripts/rn-fast-runner/**/DerivedData/
 # deepsec scanner workspace (local-only — config, data/<id>/INFO.md, scan output)
 .deepsec/
 
-# codex-pair (per-developer opt-in; marker presence enables the hook)
-.codex-pair-context.md
-.codex-pair-log.jsonl
-.codex-pair-cache/
-.codex-pair-state/
+# codex-pair (per-developer opt-in; marker presence enables the hook).
+# Per ADR-092, every state artifact (marker, log, cache, ignore globs,
+# pause sentinel, inflight locks) nests under a single directory so one
+# line covers everything including future additions.
+.codex-pair/