feat(investigations): add event impact and work-order feedback flows

Add isolated burst and pollution impact evidence, parallel work-order workflows, persisted notifications and graph updates.

Checkpoint current code. Known follow-ups remain for large pollution result previews and graceful geometry failure.

app/mcp/presentation_preview.py

@@ -5,8 +5,34 @@ from uuid import NAMESPACE_URL, uuid5
 from app.mcp.models import QueryResult
 
 
+def saved_burst_result_preview(result: QueryResult, task_id: str) -> dict | None:
+    """Keep durable full-network results usable without copying node arrays inline."""
+    if result.source != "run_burst_simulation" or not result.evidence_id:
+        return None
+    data = result.data if isinstance(result.data, dict) else {}
+    analysis = data.get("result", {})
+    impact = analysis.get("impact") if isinstance(analysis, dict) else None
+    if not isinstance(impact, dict):
+        return None
+    summary = {key: value for key, value in impact.items()
+               if key not in {"comparisons", "grades", "unavailable_node_ids"}}
+    summary["unavailable_node_count"] = len(impact.get("unavailable_node_ids", []))
+    summary["grades"] = [
+        {**{key: value for key, value in grade.items() if key != "node_ids"},
+         "node_count": len(grade.get("node_ids", []))} for grade in impact.get("grades", [])
+    ]
+    preview = {
+        "resource_uri": f"tjwater://tasks/{task_id}/evidence/{result.evidence_id}",
+        "parameters": data.get("parameters", {}), "result": {"impact": summary},
+    }
+    presentation = saved_presentation_preview(result)
+    if presentation is not None:
+        preview["presentation"] = presentation
+    return preview
+
+
 def saved_presentation_preview(result: QueryResult) -> dict | None:
-    if result.source != "generate_node_coverage" or not result.evidence_id:
+    if result.source not in {"generate_node_coverage", "run_burst_simulation", "run_contaminant_simulation"} or not result.evidence_id:
         return None
     analysis = result.data.get("result") if isinstance(result.data, dict) else None
     if not isinstance(analysis, dict):
@@ -15,11 +41,18 @@ def saved_presentation_preview(result: QueryResult) -> dict | None:
     if not isinstance(payload, dict) or not payload.get("features"):
         return None
     coverage = analysis.get("coverage", {})
+    burst = result.source == "run_burst_simulation"
+    contaminant = result.source == "run_contaminant_simulation"
+    if burst and analysis.get("impact", {}).get("phase") != "after_burst_before_intervention":
+        return None
+    if contaminant and analysis.get("impact", {}).get("phase") != "after_contamination_before_intervention":
+        return None
     return {
         "command": {
             "action": "set_overlay", "mode": "geometry", "evidence_id": result.evidence_id,
             "overlay_id": f"node-coverage-{uuid5(NAMESPACE_URL, result.evidence_id)}",
-            "title": "节点空间覆盖示意",
+            "title": ("爆管后、处置前的预计影响范围（米水头）" if burst else
+                      "水污染传播预计影响范围（处置前情景）" if contaminant else "节点空间覆盖示意"),
         },
         "display_only": True,
         "coverage_status": coverage.get("status"),