feat: add Codex CLI as a first-class fourth platform (#35)

Rebuilt from scratch following Codex CLI's actual architecture (as
outlined in the review on PR #26). Closes the integration gap with a
proper build adapter, correct install paths, TOML agent files, and
all the architectural differences documented and tested.

What changed vs the previous attempt (PR #26):

- Agents: build adapter generates .toml files (name/description/
  developer_instructions) into dist/codex-cli/.codex/agents/ instead
  of copying .md files with sed transforms
- Skills: installed to .agents/skills/ (correct Codex discovery path)
  instead of .codex/skills/
- Dispatcher: AGENTS.md uses a root-context orchestration header that
  works within agents.max_depth=1 constraints; named-agent routing
  replaced with embedded-instructions workaround for the known
  spawn_agents limitation (openai/codex#15250)
- Tool compat: AskUserQuestion and request_user_input removed; all
  prompts adapted to Codex's actual tool set and approval/confirmation
  flow
- Installer/updater: launchme.sh --platform codex-cli and updateme.sh
  with Codex auto-detection, creating the correct split layout
  (AGENTS.md + .codex/agents/ + .codex/config.toml + .agents/skills/)
- Tests: new per-adapter test suite (tests/adapters/codex-cli/),
  install/update smoke (tests/scripts/codex-cli-install.test.sh), and
  a four-platform parity gate that proves Codex changes do not regress
  Claude Code, Gemini CLI, or OpenCode
- Docs: new codex-cli.md guide, codex-migration.md for users switching
  from other platforms, and README/getting-started/examples updated for
  four-platform positioning
- Bash harness: .gitattributes added to enforce LF on .sh files;
  harness LF-normalized so tests/run.sh works on Windows checkouts
- .gitignore: .planning/ added (internal GSD workflow artifacts)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/examples.md

@@ -155,6 +155,57 @@ Practical scenarios showing how the Crew works in daily life. Each example shows
 
 ---
 
+## Codex CLI session examples
+
+These examples show how to start and use the Crew with Codex CLI specifically.
+
+### Install and launch
+
+```bash
+# Install Codex CLI
+npm i -g @openai/codex@latest
+
+# Install the Crew for Codex CLI
+bash scripts/launchme.sh --platform codex-cli
+
+# Launch Codex in your vault
+codex -C /path/to/your-vault
+```
+
+### Verify the layout before your first session
+
+```bash
+# Non-interactive discovery smoke — confirms agents, skills, and dispatcher are visible
+codex exec -C /path/to/your-vault "List the project custom agents under .codex/agents, the repo skills under .agents/skills, and the dispatcher file used in this workspace."
+
+# Check MCP server visibility
+codex -C /path/to/your-vault mcp list
+```
+
+### Using agents and skills inside Codex
+
+Once inside the interactive `codex` session, the Crew works the same way as on other platforms — just talk naturally:
+
+```
+"Initialize my vault"          → /onboarding skill starts
+"Save this note: quick idea"   → Scribe agent captures it
+"Triage my inbox"              → /inbox-triage skill runs
+"Check my email"               → /email-triage skill scans Gmail
+"Weekly review"                → /vault-audit skill audits vault
+```
+
+### Update after a git pull
+
+```bash
+cd /path/to/your-vault/My-Brain-Is-Full-Crew
+git pull
+bash scripts/updateme.sh --platform codex-cli
+```
+
+For the full runtime smoke matrix covering all 8 agents, all 14 skills, bounded child-agent chaining, and MCP visibility, see [docs/codex-cli.md](codex-cli.md).
+
+---
+
 ## Daily Workflow Cheat Sheet
 
 | Time | What to say | Skill/Agent |