reap: cascade orgs → companies → teams → agents

Selecting a team/company/org in the Agents sidebar used to only
delete the grouping row; the agents inside survived, ungrouped.
Not what the user wanted, and it left a trail of orphaned runtime
state (containers, .brain files, DB rows) behind.

Backend — POST /api/claws/batch-delete is now a universal cascade
reaper. Body accepts { ids?, teams?, companies?, orgs? } in any
combination. The server walks org → companies_of_org →
teams_of_company → agents_of_team, dedupes against explicit ids,
and hard-purges every unique agent (deprovision ZeroClaw runtime,
tear down sandbox container, unlink .brain/.onion files,
transactional agents::hard_purge). Group rows are deleted last; FK
cascades on team_members, company_teams, org_companies, and
loop_agents/teams/orgs clean up the join tables. Every stage
streams SSE.

Three new cm-db helpers wire the walk: agents_of_team,
teams_of_company, companies_of_org — all DISTINCT selects on the
existing join tables.

Frontend — Dashboard's Agents-tier StructureTree now sets
selectLevel="*" (was "claw"), so the Wrench → checkbox affordance
appears on org/company/team/agent nodes alike; the same-level
invariant in onToggleSelect still prevents mixed batches.
ReapProgressModal collapses to a single POST regardless of kind —
body key derived from kind — and its subtitle is honest:
"Cascading through every agent inside — permanent."

.sqlx/query-640d23c926f2354e6b22fc7a406635e1019efaf74b0a0e95a0c92c7997b9c005.json

@@ -0,0 +1,22 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "SELECT DISTINCT team_id FROM company_teams WHERE company_id = $1",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "team_id",
+        "type_info": "Uuid"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Uuid"
+      ]
+    },
+    "nullable": [
+      false
+    ]
+  },
+  "hash": "640d23c926f2354e6b22fc7a406635e1019efaf74b0a0e95a0c92c7997b9c005"
+}