fix(quotas): address review: resume claims, agent bucket rule, UI races

- A tool continuation refused for usage now releases the resume claim it
  took; before, retries got a 409 until the stale claim was reverted.
- Agent traffic is any row with an agent key or an agent id, so keyless
  agents and workflow nodes count toward the agent bucket, not direct.
- The user quota modal discards responses for a previously opened user.
- The usage meter shows every limited bucket, not only 'all'.
- Restore the class separator on the analytics stat card that a formatter
  run removed, and align the OpenRouter DeepSeek description with its rates.

docs/content/Deploying/Usage-Quotas.mdx

@@ -106,4 +106,4 @@ A `PUT` body sets, per budget, a limit or the unlimited flag; leave both out to
 { "token_limit": 2000000, "cost_unlimited": true, "note": "Research team" }
 ```
 
-`bucket` (default `all`) narrows a policy to `direct` traffic (chat without an agent) or `agent` traffic (anything that runs through an agent). A request must fit both its own bucket and `all`. The dashboard edits `all`.
+`bucket` (default `all`) narrows a policy to `direct` traffic (chat without an agent) or `agent` traffic (anything that runs through an agent, whether or not the agent has an API key). A request must fit both its own bucket and `all`. The dashboard edits `all`.