feat: focus priority, focus links, task list assignment, lists drag-and-drop, URL display fixes

- Focus page: turn sequence number into persistent editable priority (focus_priority column)
- Focus detail: add links section (add existing, create new, unlink) via focus_links junction table
- Focus detail: add copy and inline edit for checklist items
- Task detail lists tab: add existing list assignment and unlink actions
- Lists page: add drag-and-drop reorder support
- Links/bookmarks pages: remove artificial URL truncation, use CSS ellipsis

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

routers/tasks.py

@@ -235,6 +235,7 @@ async def task_detail(
     # Tab-specific data
     tab_data = []
     all_contacts = []
+    all_lists = []
 
     if tab == "notes":
         result = await db.execute(text("""
@@ -268,6 +269,13 @@ async def task_detail(
             ORDER BY l.sort_order, l.created_at DESC
         """), {"tid": task_id})
         tab_data = [dict(r._mapping) for r in result]
+        # Available lists for add dropdown (not already assigned to this task)
+        result = await db.execute(text("""
+            SELECT id, name FROM lists
+            WHERE is_deleted = false AND (task_id IS NULL OR task_id != :tid)
+            ORDER BY name
+        """), {"tid": task_id})
+        all_lists = [dict(r._mapping) for r in result]
 
     elif tab == "decisions":
         result = await db.execute(text("""
@@ -315,7 +323,7 @@ async def task_detail(
         "request": request, "sidebar": sidebar, "item": item,
         "domain": domain, "project": project, "parent": parent,
         "subtasks": subtasks, "tab": tab, "tab_data": tab_data,
-        "all_contacts": all_contacts, "counts": counts,
+        "all_contacts": all_contacts, "all_lists": all_lists, "counts": counts,
         "running_task_id": running_task_id,
         "page_title": item["title"], "active_nav": "tasks",
     })
@@ -471,6 +479,31 @@ async def quick_add(
 
 # ---- Contact linking ----
 
+@router.post("/{task_id}/lists/add")
+async def add_list_to_task(
+    task_id: str,
+    list_id: str = Form(...),
+    db: AsyncSession = Depends(get_db),
+):
+    await db.execute(text(
+        "UPDATE lists SET task_id = :tid, updated_at = now() WHERE id = :lid"
+    ), {"tid": task_id, "lid": list_id})
+    await db.commit()
+    return RedirectResponse(url=f"/tasks/{task_id}?tab=lists", status_code=303)
+
+
+@router.post("/{task_id}/lists/{list_id}/remove")
+async def remove_list_from_task(
+    task_id: str, list_id: str,
+    db: AsyncSession = Depends(get_db),
+):
+    await db.execute(text(
+        "UPDATE lists SET task_id = NULL, updated_at = now() WHERE id = :lid AND task_id = :tid"
+    ), {"tid": task_id, "lid": list_id})
+    await db.commit()
+    return RedirectResponse(url=f"/tasks/{task_id}?tab=lists", status_code=303)
+
+
 @router.post("/{task_id}/contacts/add")
 async def add_contact(
     task_id: str,