feat: agent authoring & doc generation (WP-0007, v1.4.0)

New authoring tooling and a fix for the doc-regeneration defect it exposed.

Added:
- src/kaizen_agentic/agent_docs.py — render + idempotent upsert of the
  CLAUDE.md "## Installed Agents" section (shared by installer and CLI)
- `kaizen-agentic docs generate [--check]` — idempotent doc refresh / CI gate
- `kaizen-agentic create-agent` — scaffold a schema-valid agent
- Frontmatter schema validation in `kaizen-agentic validate`
  (required name/description/category, known category, valid memory/model)
- tests: test_agent_docs, test_validate_schema, test_create_agent

Fixed:
- _update_documentation regex duplicated the Installed Agents block on every
  run (stopped at the first ### subheading) — now idempotent
- declared frontmatter `category` is authoritative (heuristic is fallback)
- list_installed_agents reads the frontmatter name, not the filename
- renamed agent-project-management.md -> agent-project-assistant.md to satisfy
  the agent-<name>.md convention (eliminates a name/filename collision that
  caused install/update to write a divergent duplicate)
- test_cli_error_handling no longer installs into the repo root (uses tmp)

Version 1.4.0; CHANGELOG, CLI cheat sheet, agency-framework, TODO updated.
Workplan KAIZEN-WP-0007 closed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/CLI_CHEAT_SHEET.md

@@ -52,9 +52,28 @@ kaizen-agentic remove old-agent-name
 
 # Project status
 kaizen-agentic status                    # Show current project status
-kaizen-agentic validate                  # Validate agent installation
+kaizen-agentic validate                  # Validate agents (incl. frontmatter schema)
 ```
 
+### Authoring & Docs (WP-0007)
+```bash
+# Scaffold a new schema-valid agent (agents/agent-<name>.md)
+kaizen-agentic create-agent my-agent -c testing -d "What it does"
+kaizen-agentic create-agent my-agent     # prompts for category + description
+kaizen-agentic create-agent my-agent --force   # overwrite existing
+
+# Refresh the CLAUDE.md "Installed Agents" section from agent metadata
+kaizen-agentic docs generate             # idempotent rewrite
+kaizen-agentic docs generate --check     # CI gate: non-zero if out of date
+
+# validate enforces required name/description/category, valid category,
+# and valid memory/model values
+kaizen-agentic validate
+```
+
+After adding or editing agents, run `make agents-sync-package` so the packaged
+`data/agents/` copies stay in parity (release-check gate).
+
 ### Project Metrics (ADR-004)
 ```bash
 # Record outcome at session close