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.

docsgpt/agents/headless_runner.py

@@ -87,7 +87,9 @@ def run_agent_headless(
     if not owner:
         raise ValueError("Agent config is missing user_id; cannot run headless.")
     decoded_token = {"sub": owner}
-    exceeded = QuotaService.check(owner, "agent" if agent_config.get("key") else "direct")
+    # An agent run is agent traffic whether or not the agent has a key yet.
+    is_agent_run = bool(agent_config.get("key") or _resolve_agent_id(agent_config))
+    exceeded = QuotaService.check(owner, "agent" if is_agent_run else "direct")
     if exceeded is not None:
         raise QuotaExceededError(exceeded)