fix: Anthropic purge — remove Claude from active fleet config

Closes #1143. Completes the Anthropic purge across the-nexus repo
to match timmy-config PR #440. Removes Claude as an active provider,
replaces with Gemini/Kimi in all operational config.

Golden state: Kimi K2.5 (primary) > Gemini 2.5 Pro (fallback) > Ollama (terminal)

Changes across 16 files:

CONFIG (provider references removed):
- config/deepdive.env.example: model → google/gemini-2.5-pro, Anthropic block purged
- scaffold/deep-dive/.env.example: ANTHROPIC_API_KEY removed
- scaffold/deep-dive/synthesis/synthesis_prompt.txt: Claude → Kimi/Gemini
- scaffold/deep-dive/aggregator/blog_fetcher.py: annotated as research source
- intelligence/deepdive/docker-compose.yml: cleaned comment

FLEET (Claude references deprecated):
- fleet/fleet-routing.json: ezra model → google/gemini-2.5-pro
- fleet/hermes-trismegistus/: full lane deprecated with header
- docs/FLEET_VOCABULARY.md: fallback chain → Kimi > Gemini > Ollama
- intelligence/deepdive/OPERATIONAL_READINESS.md: Anthropic → Gemini

FRONTEND (Claude → Gemini in Three.js world):
- app.js: agent station, simulation, chat prefix, status panels → Gemini
- style.css: .tag-claude → .tag-gemini, .chat-msg-claude → .chat-msg-gemini
- portals.json: claude → gemini
- world_state.json: Claude → Gemini
- nexus/components/agent-presence-panel.html: Claude → Gemini
- nexus/components/heartbeat-briefing-panel.html: Claude status → Gemini standby

PRESERVED (intentionally not changed):
- CLAUDE.md (canonical doc name)
- Historical audits, changelogs, reviews
- Git hooks (stale-pr-closer pattern matching)
- Secret detection hooks (catches leaked Anthropic keys)
- Research/competitor monitoring configs (annotated)
- Test files (test_repo_truth.py)

intelligence/deepdive/OPERATIONAL_READINESS.md

@@ -152,7 +152,7 @@ curl http://localhost:4000/v1/models
 
 If the endpoint is down, either:
 1. Start it: `llama-server -m model.gguf --port 4000 -ngl 999 --jinja`
-2. Or change `synthesis.llm_endpoint` in `config.yaml` to an alternative (e.g., OpenRouter, Kimi, Anthropic).
+2. Or change `synthesis.llm_endpoint` in `config.yaml` to an alternative (e.g., OpenRouter, Kimi, Gemini).
 
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