R4 backend: team org-chart + leaderboard, Stripe credits, workspace apps

- GET /api/team/orgchart — each member grouped with the claws they manage
  (agents.managed_by); GET /api/team/leaderboard — every claw ranked by
  its real usage_events rollup (credits/tokens/runs, zeros included).
  Both tested against real Postgres.
- Stripe Buy-credits (the Slack/Clerk integration pattern): [billing]
  config (stripe keys + price + webhook secret + credits_per_pack);
  POST /api/credits/checkout opens a real Checkout Session; POST
  /api/billing/stripe verifies Stripe's t=,v1= HMAC (constant-time) and
  grants one credit lot, idempotent on the session id; GET
  /api/billing/config gates the button (honest degradation when unset).
  Offline tests: signed grant + replay no-double-grant + forged-sig 400 +
  config flag. Live checkout creation deferred to a CM_LIVE_STRIPE test.
- /apps global page support: clawId now optional on connect + directory;
  absent => workspace-wide connection (app_connections.agent_id NULL) via
  new connections::list_for_workspace.
- ApiError gains a From<sqlx::Error> so inline queries use ? cleanly.

cm-api 10 test files incl. team_tabs (2) + stripe_billing (3); clippy clean.

Co-Authored-By: Claude Fable 5 <[email protected]>

.sqlx/query-92a267bd4b7396576c1ef86ec90cb04fcc25a653a03d87fb43f139f1995464d5.json

@@ -0,0 +1,64 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "SELECT u.id AS user_id, u.display_name, u.role, u.email,\n                  a.id AS claw_id, a.name AS claw_name, a.job_title, a.accent\n           FROM users u\n           JOIN agents a ON a.managed_by = u.id\n           WHERE u.workspace_id = $1\n           ORDER BY u.display_name, a.name",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "user_id",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 1,
+        "name": "display_name",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 2,
+        "name": "role",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 3,
+        "name": "email",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 4,
+        "name": "claw_id",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 5,
+        "name": "claw_name",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 6,
+        "name": "job_title",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 7,
+        "name": "accent",
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Uuid"
+      ]
+    },
+    "nullable": [
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "92a267bd4b7396576c1ef86ec90cb04fcc25a653a03d87fb43f139f1995464d5"
+}