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.

planner/AGENTS.md

@@ -23,7 +23,7 @@ need human decisions or external resources are filed as vault procurement items
 (`$OPS_REPO_ROOT/vault/pending/*.md`) instead of being escalated. Phase 3
 (file-at-constraints): identify the top 3 unresolved prerequisites that block
 the most downstream objectives — file issues as either `backlog` (code changes,
-dev-agent) or `action` (run existing formula, action-agent). **Stuck issues
+dev-agent) or `action` (run existing formula, dispatcher). **Stuck issues
 (detected BOUNCED/LABEL_CHURN) are dispatched to the `groom-backlog` formula
 in breakdown mode instead of being re-promoted** — this breaks the ping-pong
 loop by splitting them into dev-agent-sized sub-issues. **Human-blocked issues