feat(websearch): dynamic hook timeout from config + grok-code default

- Hook timeout now computed from max provider timeout + 30s buffer
- Removes hardcoded HOOK_TIMEOUT_SECONDS constant
- ensureHookConfig() now updates timeout when it changes
- Default OpenCode model changed from gpt-5-nano to grok-code
- Default OpenCode timeout changed from 60s to 90s
- Single source of truth: config.yaml controls all timeouts

lib/hooks/websearch-transformer.cjs

@@ -13,7 +13,7 @@
  *   CCS_WEBSEARCH_GEMINI=1         - Enable Gemini CLI provider
  *   CCS_WEBSEARCH_OPENCODE=1       - Enable OpenCode provider
  *   CCS_WEBSEARCH_GROK=1           - Enable Grok CLI provider
- *   CCS_WEBSEARCH_OPENCODE_MODEL   - OpenCode model (default: opencode/gpt-5-nano)
+ *   CCS_WEBSEARCH_OPENCODE_MODEL   - OpenCode model (default: opencode/grok-code)
  *   CCS_DEBUG=1                    - Enable debug output
  *
  * Exit codes:
@@ -61,8 +61,8 @@ const PROVIDER_CONFIG = {
 
   opencode: {
     // Model to use (can be overridden via CCS_WEBSEARCH_OPENCODE_MODEL env var)
-    model: 'opencode/gpt-5-nano',
-    // Alternative models: opencode/gpt-4o, opencode/claude-3.5-sonnet
+    model: 'opencode/grok-code',
+    // Alternative models: opencode/gpt-4o, opencode/claude-3.5-sonnet, opencode/gpt-5-nano
 
     // Provider-specific: OpenCode has built-in web search via Zen
     toolInstruction: 'Search the web using your built-in capabilities.',