phase: 23_llm_rate_responsiveness

Phase 23 final verification complete — all green.

```
VERIFIED (criteria)
1  /api/llm/snapshot windows ≈2 s live (1.98–2.00), /api/system window_seconds ≈10 s (9.996–10.005);
   /api/config llm.rate_window_seconds=2=LLM_INTERVAL_SECONDS; browser re-check ALL CHECKS PASSED
   (data/logs/23-window-{llm,system}.png — /llm prints Δ2.0s, /system footnote Δ10.0s)
2  Phase-13 pins unchanged: floor, 2×span ceiling, 8× jump gate + independent anchor — all pass
   (only import/span-line diffs in tests/; git diff confirms no assertion rewritten)
3  Live proof re-derived from artifacts: 780 rows, 0 unlabelled, windows 0.61–3.38 s, 5 starts +
   5 ends settled by poll 2 (0 unsettled), 1 m rollups max 42.3 vs raw 201.6, 0 over 300 tok/s;
   counterfactual 10 s window: median settle poll 3, |ln| 0.924 vs 0.037
4  uv run pytest: 1494 passed / 15 skipped · coverage 98.94% (floor 94) · ruff clean · pyright 0
   errors · node --check clean · bash .agents/validate.sh exit 0 · live 11 passed · store_perf 4 passed
   Dev server up, all nine sources ok. No git add/commit run; everything left in the working tree.

DOCS PASS — 4 inconsistencies fixed in AGENTS.md (last two runs above include them)
- UI conventions hero example still said the `.sub` footnote reads `Δ10.0s`; the only hero that
  prints a Δ is /llm's → now `Δ2.0s` on /llm, "at the current load" on /ups
- gap 9: "found 10 busy-edges" contradicted its own artifact (17 edges, 10 judged, 7 reported-not-
  judged) → 17; and the poll-2 ratios were a 3-of-5 cherry-pick → full five values both windows
- gap 12: the responsive-table fix is now scheduled — names 27_mobile_tables_and_audit
README, config table, .env.example, rates/prom docstrings, app/api bullets and the testing-policy
pins all re-checked against code and found consistent (store pragmas, budgets, throttle, fleet).

NOTES
- Advisory only, not phase 23: fastapi 0.153.0 → 0.156.8 available; dependencies untouched here,
  so rule 8's "update on purpose" is left to the operator.
- NOTES.md is empty in the working tree (its items became phases 24–27); left as-is, untracked-file
  rules forbid me removing it.
- Next phase: 24_dev_mtls_rollout (25–27 follow).
```

tests/test_live_fleet.py

@@ -198,7 +198,9 @@ async def test_engine_still_publishes_the_series_we_parse(engine: str,
         "gufo": ("tokens_generated_total", "tokens_prompt_total"),
         "vllm": ("generation_tokens_total", "prompt_tokens_total"),
     }[engine]
-    rates = RateEstimator(span=settings.rate_window)
+    # The span the LLM jobs really get: phase 23 spans the LLM estimator by the poll
+    # interval, not by the host's `RATE_WINDOW_SECONDS`.
+    rates = RateEstimator(span=settings.llm_interval)
     async with httpx.AsyncClient(timeout=settings.llm_timeout) as client:
         result = await collectors.fetch_engine(client, engine, base_url, api_key, rates,
                                                with_slots=engine == "gufo")
@@ -224,7 +226,9 @@ async def test_gufo_slots_answer_the_pinned_shape(settings: Settings) -> None:
     """
     if not settings.gufo_url:
         pytest.skip("GUFO_BASE_URL is unset — no gufo to ask for /slots")
-    rates = RateEstimator(span=settings.rate_window)
+    # The span the LLM jobs really get: phase 23 spans the LLM estimator by the poll
+    # interval, not by the host's `RATE_WINDOW_SECONDS`.
+    rates = RateEstimator(span=settings.llm_interval)
     async with httpx.AsyncClient(timeout=settings.llm_timeout) as client:
         result = await collectors.fetch_engine(client, "gufo", settings.gufo_url,
                                                settings.gufo_api_key, rates, with_slots=True)