research: backend routes + repo + wizard refine (behind /api/research)

Second commit of the Research + Loops arc. Builds on 0030 by lighting up
the container CRUD, the agent-slot attach/detach, the standby→processing
transition, and the wizard's one-shot LLM refine.

  GET    /api/research                     list workspace's topics
  POST   /api/research                     create (accepts wizard output)
  GET    /api/research/:id                 detail (topic + attached agents)
  PATCH  /api/research/:id                 update non-status fields
  POST   /api/research/:id/agents          attach agent (idempotent)
  DELETE /api/research/:id/agents/:agent   detach
  POST   /api/research/:id/start           standby → processing
  POST   /api/research/wizard/refine       one-shot LLM refine

The refine endpoint accumulates the workspace's default LLM provider's
stream into a JSON object (`{title, description}`) with the tight system
prompt at the top of the module. Same provider routing as agent runs
(via runtime.provider()), so a workspace already using GLM/Kimi gets it
for free.

State machine's remaining transitions (processing → reviewing on last
run_completed; reviewing → publishing via approvals gate) land with the
orchestrator hookup + approvals extension. Publish approval and loops
are separate commits still to come.

Adds cm-llm as a direct cm-api dep (previously only pulled transitively
via cm-runtime) so the refine endpoint can build a ChatRequest. Uses
sqlx::query! for compile-time verification; .sqlx cache generated on
morpheus against a fresh migrated DB.

.sqlx/query-5f8550702d365534f8778f1109b8a0d504e3b724e4d38d247de6ac2cbdd916e3.json

@@ -0,0 +1,15 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "DELETE FROM research_topic_agents WHERE topic_id = $1 AND agent_id = $2",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Uuid"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "5f8550702d365534f8778f1109b8a0d504e3b724e4d38d247de6ac2cbdd916e3"
+}