docs: update README, AGENTS, and robot-mode-design for work item status

README.md:
- Feature summary updated to mention work item status sync and GraphQL
- New config reference entry for sync.fetchWorkItemStatus (default true)
- Issue listing/show examples include --status flag usage
- Valid fields list expanded with status_name, status_category,
  status_color, status_icon_name, status_synced_at_iso
- Database schema table updated for issues table
- Ingest/sync command descriptions mention status enrichment phase
- Adaptive page sizing and graceful degradation documented

AGENTS.md:
- Robot mode example shows --status flag usage

docs/robot-mode-design.md:
- Issue available fields list expanded with status fields

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

AGENTS.md

@@ -618,6 +618,9 @@ LORE_ROBOT=1 lore issues
 lore --robot issues -n 10
 lore --robot mrs -s opened
 
+# Filter issues by work item status (case-insensitive)
+lore --robot issues --status "In progress"
+
 # List with field selection (reduces token usage ~60%)
 lore --robot issues --fields minimal
 lore --robot mrs --fields iid,title,state,draft