scrum + applier + observer: switch to paid OpenRouter ladder, add Kimi K2.6 + Gemini 2.5

Ollama Cloud was throttled across all 6 cloud rungs in iters 1-9, which
forced the loop into 0-review iterations even though the architecture
was sound. Swapping to paid OpenRouter unblocks the test path.

Ladder changes (top-of-ladder paid models, all under $0.85/M either side):
- moonshotai/kimi-k2.6     ($0.74/$4.66, 256K) — capped at 25/hr
- x-ai/grok-4.1-fast       ($0.20/$0.50, 2M)   — primary general
- google/gemini-2.5-flash  ($0.30/$2.50, 1M)   — Google reasoning
- deepseek/deepseek-v4-flash ($0.14/$0.28, 1M) — cheap workhorse
- qwen/qwen3-235b-a22b-2507  ($0.07/$0.10, 262K) — cheapest big
Existing rungs (Ollama Cloud + free OR + local qwen3.5) kept as fallback.

Per-model rate limiter (MODEL_RATE_LIMITS in scrum_master_pipeline.ts):
- Persists call timestamps to data/_kb/rate_limit_calls.jsonl so caps
  survive process restarts (autonomous loop spawns a fresh subprocess
  per iteration; without persistence each iter would reset)
- O(1) writes, prune-on-read for the rolling 1h window
- Capped models log "SKIP (rate-limited: cap N/hr reached)" and the
  ladder cycles to the next rung
- J directive 2026-04-25: 25/hr on Kimi K2.6 to bound output cost

Observer hand-review cloud tier swapped from ollama_cloud/qwen3-coder:480b
to openrouter/x-ai/grok-4.1-fast — proven to emit precise semantic
verdicts (named "AccessControl::can_access() doesn't exist" specifically
in 2026-04-25 tests instead of the heuristic fallback).

Applier patch emitter swapped from ollama_cloud/qwen3-coder:480b to
openrouter/x-ai/grok-4.1-fast (default; LH_APPLIER_MODEL +
LH_APPLIER_PROVIDER override). This was the third LLM call we missed —
without it, observer accepts a review but applier never produces patches
because its emitter was still hitting the throttled account.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/real-world/scrum_applier.ts

@@ -48,7 +48,13 @@ const TARGET_FILES = (process.env.LH_APPLIER_FILES ?? "")
 // for targeted code changes and tends to stay within the mechanical-patch
 // constraint the prompt asks for. LLM Team's /api/run?mode=patch would be
 // the ideal choice but that mode isn't registered in llm_team_ui.py yet.
-const MODEL = process.env.LH_APPLIER_MODEL ?? "qwen3-coder:480b";
+// Default patch emitter swapped to OpenRouter Grok 4.1 fast (2026-04-25)
+// after observing the prior default (ollama_cloud::qwen3-coder:480b) sit
+// at 429 throttle and never produce patches. Grok 4.1 fast: $0.20/$0.50
+// per M, 2M ctx, proven to emit precise structured patches in observer
+// hand-review tests. Override with LH_APPLIER_MODEL + LH_APPLIER_PROVIDER.
+const MODEL = process.env.LH_APPLIER_MODEL ?? "x-ai/grok-4.1-fast";
+const PROVIDER = (process.env.LH_APPLIER_PROVIDER ?? "openrouter") as "ollama_cloud" | "openrouter" | "ollama";
 const BRANCH = process.env.LH_APPLIER_BRANCH ?? `scrum/auto-apply-${Date.now().toString(36)}`;
 
 // Deny-list — anything whose path starts with one of these is skipped
@@ -206,7 +212,7 @@ ${source.slice(0, 14000)}
 
 Emit ONLY the JSON object.`;
 
-  const r = await chat({ provider: "ollama_cloud", model: MODEL, prompt, max_tokens: 2500 });
+  const r = await chat({ provider: PROVIDER, model: MODEL, prompt, max_tokens: 2500 });
   if (r.error || !r.content) return [];
 
   // Strip markdown fences if model wrapped the JSON.