Move caller dialog to Sonnet 4.6, add SearXNG for Devon, and fix stale model ids

Working-tree changes that had accumulated without being committed. The test
updates matter most: tests/test_caller_gen.py was left behind when caller_gen
started requiring voice and age in regulars_included, so the committed tree had
a failing suite that only passed locally.

- Caller dialog moves from Haiku 4.5 to Sonnet 4.6 (~$1/show to ~$3-4/show)
- Grok pinned to x-ai/grok-4.3; grok-4, grok-4-fast and grok-4.1-fast were
  retired from OpenRouter, and llm.py swallows the 404 and returns empty text,
  so a retired id makes callers go silent with nothing in the logs
- Devon's web_search now runs against SearXNG on the NAS
- Assorted TTS, audio, news, cost tracker and control-panel changes
- CLAUDE.md updated to match

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

relabel_transcripts.py

@@ -8,7 +8,7 @@ from dotenv import load_dotenv
 load_dotenv()
 API_KEY = os.getenv("OPENROUTER_API_KEY")
 TRANSCRIPT_DIR = Path(__file__).parent / "website" / "transcripts"
-MODEL = "anthropic/claude-3.5-sonnet"
+MODEL = "anthropic/claude-sonnet-4.6"
 CHUNK_SIZE = 8000
 
 PROMPT = """Insert speaker labels into this radio show transcript. The show is "Luke at the Roost". The host is LUKE. Callers call in one at a time.