Add comprehensive label documentation (bd-159, bd-163)

- Create LABELS.md with complete guide to label system
- Document label patterns, filtering, workflows, and best practices
- Add Labels section to README with examples
- Link LABELS.md in documentation section
- Close bd-159 and bd-163

Amp-Thread-ID: https://ampcode.com/threads/T-072304c3-3a03-4091-92a9-9e16b4538227
Co-authored-by: Amp <amp@ampcode.com>

.beads/issues.jsonl

@@ -64,7 +64,7 @@
 {"id":"bd-156","title":"Add daemon telemetry and metrics","description":"Track and report daemon metrics: request count, latency, cache hits/misses, error rates.","status":"open","priority":2,"issue_type":"task","created_at":"2025-10-19T20:13:59.77094-07:00","updated_at":"2025-10-19T22:47:07.913171-07:00"}
 {"id":"bd-157","title":"Improve daemon visibility and status reporting","description":"Add clear daemon status output, uptime reporting, and user-friendly error messages.","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-19T20:13:59.772435-07:00","updated_at":"2025-10-19T22:47:07.913336-07:00","closed_at":"2025-10-19T21:44:50.340047-07:00"}
 {"id":"bd-158","title":"Add daemon/client version compatibility checks","description":"Verify daemon and client versions are compatible before allowing connections.","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-19T20:13:59.774304-07:00","updated_at":"2025-10-19T22:47:07.913534-07:00","closed_at":"2025-10-19T22:29:49.795817-07:00"}
-{"id":"bd-159","title":"Enhance label functionality and documentation","description":"Improve beads label system to support cross-cutting concerns and contextual metadata beyond structured fields (status, priority, type).\n\nCurrent state: Basic label storage exists (labels table, Add/GetLabels methods)\nTarget state: Full label lifecycle management with CLI, filtering, automation, and documentation\n\nCore principles:\n- Labels for cross-cutting concerns (technical metadata, scope, effort, quality gates)\n- Structured fields for workflow state (status, priority, type remain primary)\n- Multi-dimensional tagging without schema changes\n\nSee removed LABELS.md for detailed use cases and design rationale.","status":"open","priority":2,"issue_type":"epic","created_at":"2025-10-19T20:45:24.163728-07:00","updated_at":"2025-10-19T22:47:07.913749-07:00"}
+{"id":"bd-159","title":"Enhance label functionality and documentation","description":"Improve beads label system to support cross-cutting concerns and contextual metadata beyond structured fields (status, priority, type).\n\nCurrent state: Basic label storage exists (labels table, Add/GetLabels methods)\nTarget state: Full label lifecycle management with CLI, filtering, automation, and documentation\n\nCore principles:\n- Labels for cross-cutting concerns (technical metadata, scope, effort, quality gates)\n- Structured fields for workflow state (status, priority, type remain primary)\n- Multi-dimensional tagging without schema changes\n\nSee removed LABELS.md for detailed use cases and design rationale.","status":"closed","priority":2,"issue_type":"epic","created_at":"2025-10-19T20:45:24.163728-07:00","updated_at":"2025-10-19T23:07:06.666164-07:00","closed_at":"2025-10-19T23:07:06.666164-07:00"}
 {"id":"bd-16","title":"Make auto-flush debounce duration configurable","description":"flushDebounce is hardcoded to 5 seconds. Make it configurable via environment variable BEADS_FLUSH_DEBOUNCE (e.g., '500ms', '10s'). Current 5-second value is reasonable for interactive use, but CI/automated scenarios might want faster flush. Add getDebounceDuration() helper function. Located in cmd/bd/main.go:31.","status":"closed","priority":3,"issue_type":"feature","created_at":"2025-10-16T20:46:08.971822-07:00","updated_at":"2025-10-19T22:47:07.879449-07:00","closed_at":"2025-10-18T09:47:43.22126-07:00"}
 {"id":"bd-160","title":"Implement label CLI commands (add, remove, list)","description":"Add CLI commands for label management:\n- bd label add \u003cissue\u003e \u003clabel...\u003e\n- bd label remove \u003cissue\u003e \u003clabel...\u003e\n- bd label list \u003cissue\u003e\n- bd labels (list all labels in use)\n\nBackend already has AddLabel/GetLabels/RemoveLabel methods in storage layer.","status":"closed","priority":2,"issue_type":"task","created_at":"2025-10-19T20:45:36.861324-07:00","updated_at":"2025-10-19T22:47:07.913911-07:00","closed_at":"2025-10-19T20:53:02.799889-07:00","labels":["feature","working"]}
 {"id":"bd-161","title":"Add label filtering to bd list command","description":"Support label-based filtering in bd list:\n- --label \u003clabel1,label2\u003e (AND semantics)\n- --label-any \u003clabel1,label2\u003e (OR semantics)\n- --group-by label (group results by label)\n\nEnables queries like: bd list --priority 1 --label backend,needs-review","status":"closed","priority":2,"issue_type":"task","created_at":"2025-10-19T20:45:36.863417-07:00","updated_at":"2025-10-19T22:54:43.232225-07:00","closed_at":"2025-10-19T22:54:43.232225-07:00"}