Archive completed tasks, add cleanup commands, self-documenting dashboard UI

- Archive 79 completed framework-dev tasks from tasks/ -> tasks/complete/
- status.py: add --cleanup-done and --install-cleanup-schedule commands
- Add scripts/automaton-cleanup.sh for periodic task archiving
- Dashboard: rename 'Background' tab -> 'Agent', 'Cleanup' agent -> 'Completed Task Archiver', remove redundant group headers and pill badges, dim inactive agent placeholders
- .rules.md: add Self-Documenting UI Names rule
- New tests: test_cleanup_done.py, expanded test_app.py and test_task.py

tasks/multi-agent-support/IMPLEMENTATION.md

@@ -1,65 +0,0 @@
-# Implementation: Multi-Agent Support
-
-## Changes Made
-
-### 1. Agent Configuration in `.agent.md`
-Multi-agent mode is activated by adding an `## Agent Configuration` section to `.agent.md`:
-```markdown
-## Agent Configuration
-Mode: multi-agent
-Agents:
-  - id: researcher
-    phases: [research, decomposition, design, test_design]
-  - id: implementer
-    phases: [implement]
-  - id: orchestrator
-    phases: [new, complete, human_intervention]
-    role: coordinator
-Lock timeout: 30m
-```
-When this section is absent or `Mode: single-agent` (default), all multi-agent commands are no-ops.
-
-### 2. Task claiming: `--claim` and `--release`
-- `status.py --claim --task {name} --agent {id}` creates `.state.lock` with agent ID, phase, claimed timestamp, and expiry
-- Atomic write (`.state.lock.tmp` → `.state.lock`)
-- Refuses if already claimed and not expired
-- Overclaims expired locks with warning
-- Validates agent is configured for the task's current phase
-- Default lock timeout: 30 minutes, configurable in `.agent.md`
-
-### 3. Work discovery: `--next-available` and `--available`
-- `--next-available --agent {id}` returns the highest-priority unclaimed task matching the agent's allowed phases
-- Priority: tasks closest to completion first (referee > doc_review > ... > research > new)
-- `--available --agent {id}` lists all matching tasks
-- In single-agent mode, both return a message directing to `--list`
-
-### 4. Single-agent zero-overhead guarantee
-- When no Agent Configuration exists, `--claim`, `--release`, `--next-available`, `--available` are no-ops or return guidance messages
-- No `.state.lock` files are created in single-agent mode
-- No performance overhead, no behavioral change from v1
-
-### 5. Coordinator role
-- Agent with `role: coordinator` can:
-  - Claim tasks on behalf of other agents (`--claim --agent {target} --as-coordinator`)
-  - Force-release claims (`--release --as-coordinator`)
-  - Force-transition (`--transition {phase} --force`)
-
-### 6. Lock expiry and conflict resolution
-- Locks expire after configurable timeout (default 30 min)
-- Any agent can overclaim expired locks
-- Atomic lock writes prevent race conditions
-- Locks auto-release on `complete` and `human_intervention` transitions
-
-### 7. Role binding in phase prompts
-- When multi-agent mode is active and `--agent` is provided, `status.py --task` includes agent-specific ALLOWED/FORBIDDEN sections
-- Phase prompts include `## Agent Role` section when agent is role-bound
-- `TASK_HANDOFF` signal defined for when agent can't perform a required phase
-
-## Files Modified
-- `scripts/status.py` (multi-agent commands implemented)
-- `tests/test_status.py` (existing tests cover single-agent; multi-agent requires Agent Configuration to test)
-
-## Notes
-- Multi-agent is opt-in: zero config changes needed for single-agent usage
-- The phase prompt `## Agent Role` section is documented in the `multi-agent-support/SPEC.md` but will be dynamically generated by `status.py --task` output when multi-agent is active
-- Dashboard integration for multi-agent status display is future work