feat(context-injector): introduce centralized context collection and integrate with keyword-detector

- Add ContextCollector class for managing and merging context entries across sessions
- Add types and interfaces for context management (ContextEntry, ContextPriority, PendingContext)
- Create context-injector hook for injection coordination
- Refactor keyword-detector to use context-injector instead of hook-message-injector
- Update src/index.ts to initialize context-injector infrastructure

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

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

@@ -0,0 +1,172 @@
+import { describe, it, expect, beforeEach } from "bun:test"
+import { ContextCollector } from "./collector"
+import { injectPendingContext, createContextInjectorHook } from "./injector"
+
+describe("injectPendingContext", () => {
+  let collector: ContextCollector
+
+  beforeEach(() => {
+    collector = new ContextCollector()
+  })
+
+  describe("when parts have text content", () => {
+    it("prepends context to first text part", () => {
+      // #given
+      const sessionID = "ses_inject1"
+      collector.register(sessionID, {
+        id: "ulw",
+        source: "keyword-detector",
+        content: "Ultrawork mode activated",
+      })
+      const parts = [{ type: "text", text: "User message" }]
+
+      // #when
+      const result = injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(result.injected).toBe(true)
+      expect(parts[0].text).toContain("Ultrawork mode activated")
+      expect(parts[0].text).toContain("User message")
+    })
+
+    it("uses separator between context and original message", () => {
+      // #given
+      const sessionID = "ses_inject2"
+      collector.register(sessionID, {
+        id: "ctx",
+        source: "keyword-detector",
+        content: "Context content",
+      })
+      const parts = [{ type: "text", text: "Original message" }]
+
+      // #when
+      injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(parts[0].text).toBe("Context content\n\n---\n\nOriginal message")
+    })
+
+    it("consumes context after injection", () => {
+      // #given
+      const sessionID = "ses_inject3"
+      collector.register(sessionID, {
+        id: "ctx",
+        source: "keyword-detector",
+        content: "Context",
+      })
+      const parts = [{ type: "text", text: "Message" }]
+
+      // #when
+      injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(collector.hasPending(sessionID)).toBe(false)
+    })
+
+    it("returns injected=false when no pending context", () => {
+      // #given
+      const sessionID = "ses_empty"
+      const parts = [{ type: "text", text: "Message" }]
+
+      // #when
+      const result = injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(result.injected).toBe(false)
+      expect(parts[0].text).toBe("Message")
+    })
+  })
+
+  describe("when parts have no text content", () => {
+    it("does not inject and preserves context", () => {
+      // #given
+      const sessionID = "ses_notext"
+      collector.register(sessionID, {
+        id: "ctx",
+        source: "keyword-detector",
+        content: "Context",
+      })
+      const parts = [{ type: "image", url: "https://example.com/img.png" }]
+
+      // #when
+      const result = injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(result.injected).toBe(false)
+      expect(collector.hasPending(sessionID)).toBe(true)
+    })
+  })
+
+  describe("with multiple text parts", () => {
+    it("injects into first text part only", () => {
+      // #given
+      const sessionID = "ses_multi"
+      collector.register(sessionID, {
+        id: "ctx",
+        source: "keyword-detector",
+        content: "Context",
+      })
+      const parts = [
+        { type: "text", text: "First" },
+        { type: "text", text: "Second" },
+      ]
+
+      // #when
+      injectPendingContext(collector, sessionID, parts)
+
+      // #then
+      expect(parts[0].text).toContain("Context")
+      expect(parts[1].text).toBe("Second")
+    })
+  })
+})
+
+describe("createContextInjectorHook", () => {
+  let collector: ContextCollector
+
+  beforeEach(() => {
+    collector = new ContextCollector()
+  })
+
+  describe("chat.message handler", () => {
+    it("injects pending context into output parts", async () => {
+      // #given
+      const hook = createContextInjectorHook(collector)
+      const sessionID = "ses_hook1"
+      collector.register(sessionID, {
+        id: "ctx",
+        source: "keyword-detector",
+        content: "Hook context",
+      })
+      const input = { sessionID }
+      const output = {
+        message: {},
+        parts: [{ type: "text", text: "User message" }],
+      }
+
+      // #when
+      await hook["chat.message"](input, output)
+
+      // #then
+      expect(output.parts[0].text).toContain("Hook context")
+      expect(output.parts[0].text).toContain("User message")
+    })
+
+    it("does nothing when no pending context", async () => {
+      // #given
+      const hook = createContextInjectorHook(collector)
+      const sessionID = "ses_hook2"
+      const input = { sessionID }
+      const output = {
+        message: {},
+        parts: [{ type: "text", text: "User message" }],
+      }
+
+      // #when
+      await hook["chat.message"](input, output)
+
+      // #then
+      expect(output.parts[0].text).toBe("User message")
+    })
+  })
+})