* feat(routing): per-model web-search interception rule (#3384)
Adds a per-provider/per-model interceptSearch rule (src/lib/db/interceptionRules.ts,
key_value namespace interception_rules) that overrides the existing native
web-search bypass defaults (Codex/Gemini/Claude->Claude passthrough) in
webSearchFallback.ts. Wired at the existing prepareWebSearchFallbackBody() call
site in chatCore.ts. Resolution precedence: per-model rule > provider-level rule
> existing native-bypass defaults.
This lands Phase 1-2 of the plan (rule store + search interception). Web-fetch
interception and the dashboard UI toggle are tracked as follow-up phases.
* fix(db): register interceptionRules in localDb re-export layer (db-rules gate)
* fix(db): renumber interception_rules migration 119→120 (collision with model_capability_overrides)
