feat: update_milestone tool and workspace milestone refresh

- Add update_milestone LLM tool: accepts project + milestone title to
  look up, then applies any of title/description/status changes
- WorkspaceView SSE watcher now triggers taskPanelRef.reload() on
  create_milestone and update_milestone success, so milestone groups
  appear immediately without a manual refresh

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

frontend/src/views/WorkspaceView.vue

@@ -80,7 +80,7 @@ watch(
         activeNoteId.value = tc.result.data.id as number;
       }
       if (
-        ["create_task", "update_task"].includes(tc.function) &&
+        ["create_task", "update_task", "create_milestone", "update_milestone"].includes(tc.function) &&
         tc.status === "success"
       ) {
         taskPanelRef.value?.reload();

src/fabledassistant/services/tools.py

@@ -436,6 +436,24 @@ _CORE_TOOLS = [
             },
         },
     },
+    {
+        "type": "function",
+        "function": {
+            "name": "update_milestone",
+            "description": "Update the title, description, or status of an existing milestone.",
+            "parameters": {
+                "type": "object",
+                "properties": {
+                    "project": {"type": "string", "description": "Project title the milestone belongs to"},
+                    "milestone": {"type": "string", "description": "Current milestone title to look up"},
+                    "title": {"type": "string", "description": "New title (omit to keep current)"},
+                    "description": {"type": "string", "description": "New description (omit to keep current)"},
+                    "status": {"type": "string", "enum": ["active", "completed", "cancelled"], "description": "New status (omit to keep current)"},
+                },
+                "required": ["project", "milestone"],
+            },
+        },
+    },
     {
         "type": "function",
         "function": {
@@ -1426,6 +1444,35 @@ async def execute_tool(user_id: int, tool_name: str, arguments: dict) -> dict:
             )
             return {"success": True, "type": "milestone", "data": ms.to_dict()}
 
+        elif tool_name == "update_milestone":
+            from fabledassistant.services.projects import get_project_by_title as _gpbt, list_projects as _lp
+            from fabledassistant.services.milestones import get_milestone_by_title as _gmbt, update_milestone as _um
+            project_name = arguments.get("project", "")
+            milestone_name = arguments.get("milestone", "")
+            if not project_name or not milestone_name:
+                return {"success": False, "error": "Both project and milestone are required"}
+            proj = await _gpbt(user_id, project_name)
+            if proj is None:
+                all_p = await _lp(user_id)
+                matches = [p for p in all_p if project_name.lower() in p.title.lower()]
+                proj = matches[0] if matches else None
+            if proj is None:
+                return {"success": False, "error": f"Project '{project_name}' not found"}
+            ms = await _gmbt(user_id, proj.id, milestone_name)
+            if ms is None:
+                return {"success": False, "error": f"Milestone '{milestone_name}' not found in project '{proj.title}'. Use list_milestones to see available milestones."}
+            fields: dict[str, object] = {}
+            if "title" in arguments:
+                fields["title"] = arguments["title"]
+            if "description" in arguments:
+                fields["description"] = arguments["description"]
+            if "status" in arguments:
+                fields["status"] = arguments["status"]
+            if not fields:
+                return {"success": False, "error": "No fields to update — provide at least one of: title, description, status"}
+            updated = await _um(user_id, ms.id, **fields)
+            return {"success": True, "type": "milestone", "data": updated.to_dict()}
+
         elif tool_name == "list_milestones":
             from fabledassistant.services.projects import get_project_by_title as _gpbt, list_projects as _lp
             from fabledassistant.services.milestones import get_project_milestone_summary