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.

lib/env.sh

@@ -95,10 +95,9 @@ export FORGE_GARDENER_TOKEN="${FORGE_GARDENER_TOKEN:-${FORGE_TOKEN}}"
 export FORGE_VAULT_TOKEN="${FORGE_VAULT_TOKEN:-${FORGE_TOKEN}}"
 export FORGE_SUPERVISOR_TOKEN="${FORGE_SUPERVISOR_TOKEN:-${FORGE_TOKEN}}"
 export FORGE_PREDICTOR_TOKEN="${FORGE_PREDICTOR_TOKEN:-${FORGE_TOKEN}}"
-export FORGE_ACTION_TOKEN="${FORGE_ACTION_TOKEN:-${FORGE_TOKEN}}"
 
 # Bot usernames filter: FORGE_BOT_USERNAMES > legacy CODEBERG_BOT_USERNAMES
-export FORGE_BOT_USERNAMES="${FORGE_BOT_USERNAMES:-${CODEBERG_BOT_USERNAMES:-dev-bot,review-bot,planner-bot,gardener-bot,vault-bot,supervisor-bot,predictor-bot,action-bot}}"
+export FORGE_BOT_USERNAMES="${FORGE_BOT_USERNAMES:-${CODEBERG_BOT_USERNAMES:-dev-bot,review-bot,planner-bot,gardener-bot,vault-bot,supervisor-bot,predictor-bot}}"
 export CODEBERG_BOT_USERNAMES="${FORGE_BOT_USERNAMES}"  # backwards compat
 
 # Project config (FORGE_* preferred, CODEBERG_* fallback)