feat(KB-004): add GitHub PR creation and comment monitoring

- Add PR fields (prInfo, prNumber, prUrl) to Task type and TaskStore with updatePrInfo method
- Add PR Management API endpoints: create, status, refresh with per-repo rate limiting
- Add GitHubClient for PR creation and status fetching with comment support
- Add PrSection component for PR status display and actions in dashboard
- Add PR comment monitoring engine with PrMonitor and PrCommentHandler
- Integrate PR monitoring into scheduler for automatic PR tracking
- Add comprehensive tests for PR features in all packages

packages/core/src/index.ts

@@ -1,4 +1,4 @@
 export { COLUMNS, COLUMN_LABELS, COLUMN_DESCRIPTIONS, VALID_TRANSITIONS, DEFAULT_SETTINGS, THINKING_LEVELS } from "./types.js";
-export type { Column, Task, TaskAttachment, TaskCreateInput, TaskDetail, AgentLogEntry, AgentLogType, AgentRole, BoardConfig, MergeResult, Settings, TaskStep, StepStatus, TaskLogEntry, ThinkingLevel, SteeringComment } from "./types.js";
+export type { Column, PrInfo, PrStatus, Task, TaskAttachment, TaskCreateInput, TaskDetail, AgentLogEntry, AgentLogType, AgentRole, BoardConfig, MergeResult, Settings, TaskStep, StepStatus, TaskLogEntry, ThinkingLevel, SteeringComment } from "./types.js";
 export { TaskStore } from "./store.js";
 export { canTransition, getValidTransitions, resolveDependencyOrder } from "./board.js";

packages/core/src/store.test.ts

@@ -810,6 +810,189 @@ describe("TaskStore", () => {
     });
   });
 
+  describe("updatePrInfo", () => {
+    it("adds PR info to a task without existing PR", async () => {
+      const task = await createTestTask();
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+
+      const updated = await store.updatePrInfo(task.id, prInfo);
+
+      expect(updated.prInfo).toEqual(prInfo);
+      expect(updated.log.some((l) => l.action === "PR linked" && l.outcome?.includes("#42"))).toBe(true);
+    });
+
+    it("updates existing PR info with new values", async () => {
+      const task = await createTestTask();
+      const prInfo1 = {
+        url: "https://github.com/owner/repo/pull/1",
+        number: 1,
+        status: "open" as const,
+        title: "Initial PR",
+        headBranch: "branch-1",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+      await store.updatePrInfo(task.id, prInfo1);
+
+      const prInfo2 = {
+        url: "https://github.com/owner/repo/pull/1",
+        number: 1,
+        status: "merged" as const,
+        title: "Initial PR (updated)",
+        headBranch: "branch-1",
+        baseBranch: "main",
+        commentCount: 3,
+        lastCommentAt: "2026-01-01T00:00:00.000Z",
+      };
+      const updated = await store.updatePrInfo(task.id, prInfo2);
+
+      expect(updated.prInfo?.status).toBe("merged");
+      expect(updated.prInfo?.commentCount).toBe(3);
+      expect(updated.prInfo?.lastCommentAt).toBe("2026-01-01T00:00:00.000Z");
+    });
+
+    it("clears PR info when passed null", async () => {
+      const task = await createTestTask();
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+      await store.updatePrInfo(task.id, prInfo);
+
+      const updated = await store.updatePrInfo(task.id, null);
+
+      expect(updated.prInfo).toBeUndefined();
+      expect(updated.log.some((l) => l.action === "PR unlinked")).toBe(true);
+    });
+
+    it("emits task:updated event when PR info changes", async () => {
+      const task = await createTestTask();
+      const events: any[] = [];
+      store.on("task:updated", (t) => events.push(t));
+
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+      await store.updatePrInfo(task.id, prInfo);
+
+      expect(events).toHaveLength(1);
+      expect(events[0].prInfo?.number).toBe(42);
+    });
+
+    it("does NOT emit task:updated when PR info is unchanged", async () => {
+      const task = await createTestTask();
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+      await store.updatePrInfo(task.id, prInfo);
+
+      const events: any[] = [];
+      store.on("task:updated", (t) => events.push(t));
+
+      // Update with same values (status and number unchanged)
+      await store.updatePrInfo(task.id, { ...prInfo });
+
+      // Should not emit because number and status are the same
+      expect(events).toHaveLength(0);
+    });
+
+    it("persists to disk and round-trips correctly", async () => {
+      const task = await createTestTask();
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 5,
+        lastCommentAt: "2026-03-30T12:00:00.000Z",
+      };
+
+      await store.updatePrInfo(task.id, prInfo);
+      const fetched = await store.getTask(task.id);
+
+      expect(fetched.prInfo).toEqual(prInfo);
+    });
+
+    it("updates updatedAt timestamp", async () => {
+      const task = await createTestTask();
+      const before = task.updatedAt;
+      await new Promise((r) => setTimeout(r, 10)); // Ensure time passes
+
+      const prInfo = {
+        url: "https://github.com/owner/repo/pull/42",
+        number: 42,
+        status: "open" as const,
+        title: "Fix the bug",
+        headBranch: "kb-001-fix-bug",
+        baseBranch: "main",
+        commentCount: 0,
+      };
+      const updated = await store.updatePrInfo(task.id, prInfo);
+
+      expect(updated.updatedAt).not.toBe(before);
+    });
+
+    it("serializes concurrent updates correctly", async () => {
+      const task = await createTestTask();
+
+      // Fire 5 concurrent updates
+      const promises = Array.from({ length: 5 }, (_, i) =>
+        store.updatePrInfo(task.id, {
+          url: `https://github.com/owner/repo/pull/${i + 1}`,
+          number: i + 1,
+          status: "open" as const,
+          title: `PR ${i + 1}`,
+          headBranch: `branch-${i + 1}`,
+          baseBranch: "main",
+          commentCount: i,
+        }),
+      );
+
+      await Promise.all(promises);
+
+      // Read back and verify valid JSON
+      const taskJsonPath = join(rootDir, ".kb", "tasks", task.id, "task.json");
+      const raw = await readFile(taskJsonPath, "utf-8");
+      const result = JSON.parse(raw) as Task;
+
+      // Should have exactly one of the PRs set (last one wins)
+      expect(result.prInfo).toBeDefined();
+      expect(result.prInfo!.number).toBeGreaterThanOrEqual(1);
+      expect(result.prInfo!.number).toBeLessThanOrEqual(5);
+
+      // Should have all the PR linked log entries
+      const prLogs = result.log.filter((l) => l.action === "PR linked");
+      expect(prLogs).toHaveLength(5);
+    });
+  });
+
   describe("parseDependenciesFromPrompt", () => {
     it("returns single dependency from PROMPT.md", async () => {
       const task = await store.createTask({ description: "Task with dep" });

packages/core/src/store.ts

@@ -1023,6 +1023,57 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     });
   }
 
+  /**
+   * Update or clear PR information for a task.
+   * Updates task.json atomically and emits `task:updated` event.
+   *
+   * @param id - The task ID
+   * @param prInfo - The PR info to set, or null to clear
+   * @returns The updated task
+   */
+  async updatePrInfo(
+    id: string,
+    prInfo: import("./types.js").PrInfo | null,
+  ): Promise<Task> {
+    return this.withTaskLock(id, async () => {
+      const dir = this.taskDir(id);
+      const task = await this.readTaskJson(dir);
+
+      const prevPrNumber = task.prInfo?.number;
+      const prevPrStatus = task.prInfo?.status;
+
+      if (prInfo) {
+        task.prInfo = prInfo;
+        task.log.push({
+          timestamp: new Date().toISOString(),
+          action: "PR linked",
+          outcome: `PR #${prInfo.number}: ${prInfo.url}`,
+        });
+      } else {
+        task.prInfo = undefined;
+        if (prevPrNumber) {
+          task.log.push({
+            timestamp: new Date().toISOString(),
+            action: "PR unlinked",
+            outcome: `PR #${prevPrNumber} removed`,
+          });
+        }
+      }
+
+      task.updatedAt = new Date().toISOString();
+
+      await this.atomicWriteTaskJson(dir, task);
+      if (this.watcher) this.taskCache.set(id, { ...task });
+
+      // Only emit if PR info actually changed
+      if (prevPrNumber !== prInfo?.number || prevPrStatus !== prInfo?.status) {
+        this.emit("task:updated", task);
+      }
+
+      return task;
+    });
+  }
+
   /**
    * Read all historical agent log entries for a task from its agent log file.
    * Returns entries in chronological order (oldest first).

packages/core/src/types.ts

@@ -5,6 +5,20 @@ export type ThinkingLevel = (typeof THINKING_LEVELS)[number];
 export const COLUMNS = ["triage", "todo", "in-progress", "in-review", "done"] as const;
 export type Column = (typeof COLUMNS)[number];
 
+export type PrStatus = "open" | "closed" | "merged";
+
+export interface PrInfo {
+  url: string;
+  number: number;
+  status: PrStatus;
+  title: string;
+  headBranch: string;
+  baseBranch: string;
+  commentCount: number;
+  lastCommentAt?: string;
+  lastCheckedAt?: string;
+}
+
 export type StepStatus = "pending" | "in-progress" | "done" | "skipped";
 
 export interface TaskStep {
@@ -81,6 +95,8 @@ export interface Task {
   baseBranch?: string;
   attachments?: TaskAttachment[];
   steeringComments?: SteeringComment[];
+  /** PR information for tasks linked to GitHub pull requests */
+  prInfo?: PrInfo;
   log: TaskLogEntry[];
   size?: "S" | "M" | "L";
   reviewLevel?: number;
@@ -141,6 +157,9 @@ export interface Settings {
    *  Defaults to `"KB"`. Only affects new tasks — existing tasks retain
    *  their original IDs. */
   taskPrefix?: string;
+  /** Whether GitHub token is configured for PR operations (read-only, set by server).
+   *  When false, PR creation features are disabled in the UI. */
+  githubTokenConfigured?: boolean;
   /** When true, merge commit messages include the task ID as the conventional
    *  commit scope (e.g. `feat(KB-001): ...`). When false, the scope is
    *  omitted (e.g. `feat: ...`). Default: true. */