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/collector.ts

@@ -0,0 +1,85 @@
+import type {
+  ContextEntry,
+  ContextPriority,
+  PendingContext,
+  RegisterContextOptions,
+} from "./types"
+
+const PRIORITY_ORDER: Record<ContextPriority, number> = {
+  critical: 0,
+  high: 1,
+  normal: 2,
+  low: 3,
+}
+
+const CONTEXT_SEPARATOR = "\n\n---\n\n"
+
+export class ContextCollector {
+  private sessions: Map<string, Map<string, ContextEntry>> = new Map()
+
+  register(sessionID: string, options: RegisterContextOptions): void {
+    if (!this.sessions.has(sessionID)) {
+      this.sessions.set(sessionID, new Map())
+    }
+
+    const sessionMap = this.sessions.get(sessionID)!
+    const key = `${options.source}:${options.id}`
+
+    const entry: ContextEntry = {
+      id: options.id,
+      source: options.source,
+      content: options.content,
+      priority: options.priority ?? "normal",
+      timestamp: Date.now(),
+      metadata: options.metadata,
+    }
+
+    sessionMap.set(key, entry)
+  }
+
+  getPending(sessionID: string): PendingContext {
+    const sessionMap = this.sessions.get(sessionID)
+
+    if (!sessionMap || sessionMap.size === 0) {
+      return {
+        merged: "",
+        entries: [],
+        hasContent: false,
+      }
+    }
+
+    const entries = this.sortEntries([...sessionMap.values()])
+    const merged = entries.map((e) => e.content).join(CONTEXT_SEPARATOR)
+
+    return {
+      merged,
+      entries,
+      hasContent: entries.length > 0,
+    }
+  }
+
+  consume(sessionID: string): PendingContext {
+    const pending = this.getPending(sessionID)
+    this.clear(sessionID)
+    return pending
+  }
+
+  clear(sessionID: string): void {
+    this.sessions.delete(sessionID)
+  }
+
+  hasPending(sessionID: string): boolean {
+    const sessionMap = this.sessions.get(sessionID)
+    return sessionMap !== undefined && sessionMap.size > 0
+  }
+
+  private sortEntries(entries: ContextEntry[]): ContextEntry[] {
+    return entries.sort((a, b) => {
+      const priorityDiff = PRIORITY_ORDER[a.priority] - PRIORITY_ORDER[b.priority]
+      if (priorityDiff !== 0) return priorityDiff
+      return a.timestamp - b.timestamp
+    })
+  }
+}
+
+export const contextCollector = new ContextCollector()