feat: add general /supports list endpoint with status/taken_by filters

- New GET /supports endpoint for listing all support tickets across projects
- Supports optional ?status= and ?taken_by= (me|null|username) query params
- Ordered by created_at descending
- Complements the existing scoped /supports/{project_code}/{milestone_id} endpoint

app/api/routers/misc.py

@@ -524,6 +524,35 @@ def _serialize_support(db: Session, support: Support) -> dict:
     }
 
 
+@router.get("/supports", tags=["Supports"])
+def list_all_supports(
+    status: str | None = None,
+    taken_by: str | None = None,
+    db: Session = Depends(get_db),
+    current_user: models.User = Depends(get_current_user_or_apikey),
+):
+    """List support tickets across all projects. Optional status/taken_by filters."""
+    query = db.query(Support)
+
+    if status:
+        query = query.filter(Support.status == SupportStatus(status))
+
+    if taken_by == "me":
+        query = query.filter(Support.assignee_id == current_user.id)
+    elif taken_by == "null":
+        query = query.filter(Support.assignee_id.is_(None))
+    elif taken_by:
+        assignee = db.query(models.User).filter(models.User.username == taken_by).first()
+        if assignee:
+            query = query.filter(Support.assignee_id == assignee.id)
+        else:
+            return []
+
+    query = query.order_by(Support.created_at.desc())
+    supports = query.all()
+    return [_serialize_support(db, s) for s in supports]
+
+
 @router.get("/supports/{project_code}/{milestone_id}", tags=["Supports"])
 def list_supports(project_code: str, milestone_id: int, db: Session = Depends(get_db)):
     project = db.query(models.Project).filter(models.Project.project_code == project_code).first()