feat(keyword-detector): add enabled_expansions config for allowlist control

Add optional enabled_expansions field to keyword_detector config schema.
When set, acts as an allowlist - only those expansion types fire.
Empty array disables all expansions. Absent field keeps all enabled (backward-compatible).
Also supports coexistence with disabled_keywords denylist for fine-grained control.

- src/config/schema/keyword-detector.ts: add enabled_expansions field
- src/hooks/keyword-detector/detector.ts: apply allowlist filter in detectKeywordsWithType
- src/hooks/keyword-detector/hook.ts: pass enabled_expansions from config
- src/hooks/keyword-detector/index.test.ts: add 4 tests for enabled_expansions behavior
- assets/oh-my-opencode.schema.json: regenerate schema

src/config/schema/keyword-detector.ts

@@ -4,6 +4,7 @@ export const KeywordTypeSchema = z.enum(["ultrawork", "search", "analyze", "team
 export type KeywordType = z.infer<typeof KeywordTypeSchema>
 
 export const KeywordDetectorConfigSchema = z.object({
+  enabled_expansions: z.array(KeywordTypeSchema).optional(),
   disabled_keywords: z.array(KeywordTypeSchema).optional(),
 })