[AAASM-3940] ✨ (docs): Add org-level CLAUDE.md and AGENTS.md baseline

[Chisanan232]

Jira Ticket

• AAASM-3940

Summary

• Adds the org-level AGENTS.md baseline (Codex-facing) and points the existing CLAUDE.md at the upcoming .claude/rules/ and .claude/skills/ directories, per Epic AAASM-3938 (org-level AI onboarding POC).
• Depends on [AAASM-3939] 📝 (workspace): Add org-level AI workspace layout doc #25 (AAASM-3939, .claude/WORKSPACE.md) — this branch is stacked on v0.1.0/AAASM-3939/define_workspace_layout and should not be merged before [AAASM-3939] 📝 (workspace): Add org-level AI workspace layout doc #25.

Changes

• CLAUDE.md: additive "AI tooling: rules, skills, and Codex parity" section — no existing content rewritten or duplicated.
• AGENTS.md (new): compact, self-sufficient Codex entry point — product summary, repo map, commit/branch/PR conventions, remote-naming gotcha, CI reality, JIRA conventions, project policy, and a pointer to .claude/rules/ and .claude/skills/ (with a note that org policy in those rules/skills applies to Codex work too, even though Codex has no native skill loader).

Validation

• Content reviewed for accuracy
• Links verified
• No unintended scope changes

Checklist

• PR title follows: [<ticket ID>] <GitEmoji> (<change scope category>): <key point as summary>
• PR body follows this template

[Chisanan232]

Claude Code review — AAASM-3940

CI: Red, same org-wide Actions billing-block as every other PR in this stack (see #25's comment for detail) — not caused by this change.

Scope vs ticket: Matches AAASM-3940's acceptance criteria — CLAUDE.md gets a compact additive pointer section (verified via git diff against pre-Epic master: 16 lines added, 0 lines removed from the existing file — no rewriting), and AGENTS.md is a new, self-sufficient Codex baseline.

Side effects: None on existing CLAUDE.md content — confirmed pure addition, not a rewrite.

Note (non-blocking): 3946's dogfooding pass later found AGENTS.md doesn't inline the policy from 05-context-boundary.md/06-audit-trail.md (added in #27), so a Codex session is structurally blind to that guidance in a way a Claude Code session isn't. Tracked as follow-up item #6 in #33 — not an AAASM-3940 AC gap, since those rule files didn't exist yet when this ticket was scoped.

Frontend: N/A.

Recommend: ready to merge, after #25.