refactor(keyword-detector): decouple from claude-code-hooks via ContextCollector pipeline

- keyword-detector now registers keywords to ContextCollector
- context-injector consumes and injects via chat.message hook
- Removed keyword detection logic from claude-code-hooks
- Hook order: keyword-detector → context-injector → claude-code-hooks
- ultrawork now works even when claude-code-hooks is disabled

src/features/context-injector/injector.test.ts

@@ -133,7 +133,7 @@ describe("createContextInjectorHook", () => {
   })
 
   describe("chat.message handler", () => {
-    it("is a no-op (context injection moved to messages transform)", async () => {
+    it("injects pending context into output parts", async () => {
       // #given
       const hook = createContextInjectorHook(collector)
       const sessionID = "ses_hook1"
@@ -152,8 +152,9 @@ describe("createContextInjectorHook", () => {
       await hook["chat.message"](input, output)
 
       // #then
-      expect(output.parts[0].text).toBe("User message")
-      expect(collector.hasPending(sessionID)).toBe(true)
+      expect(output.parts[0].text).toContain("Hook context")
+      expect(output.parts[0].text).toContain("User message")
+      expect(collector.hasPending(sessionID)).toBe(false)
     })
 
     it("does nothing when no pending context", async () => {