fix: chore(26a): delete action-agent.sh, action-poll.sh, and action/AGENTS.md (#65)

- Delete action/ directory and all its contents
- Remove action-bot from bin/disinto bot token mapping and collaborator lists
- Remove FORGE_ACTION_TOKEN from lib/env.sh and .env.example
- Remove action-bot from FORGE_BOT_USERNAMES in lib/env.sh and .env.example
- Update .woodpecker/agent-smoke.sh to remove action script checks
- Update AGENTS.md: remove action agent from description and table
- Update lib/AGENTS.md: remove action-agent references from sourced by columns
- Update docs/PHASE-PROTOCOL.md: remove action-agent reference
- Update docs/AGENT-DESIGN.md: remove action-agent from agent table
- Update planner/AGENTS.md: update action formula execution reference
- Update README.md: update formula-driven execution reference

Part of #26 — retire action-agent system.

README.md

@@ -123,7 +123,7 @@ disinto/
 │   └── best-practices.md # Gardener knowledge base
 ├── planner/
 │   ├── planner-poll.sh   # Cron entry: weekly vision gap analysis
-│   └── (formula-driven)  # run-planner.toml executed by action-agent
+│   └── (formula-driven)  # run-planner.toml executed by dispatcher
 ├── vault/
 │   ├── vault-poll.sh     # Cron entry: process pending dangerous actions
 │   ├── vault-agent.sh    # Classifies and routes actions (claude -p)