feat(KB-334): change default task prefix from KB to FN

- Change default taskPrefix from KB to FN and branch naming from kb/ to fusion/
- Update all test expectations and patterns for new naming convention
- Update settings UI placeholder text to reflect FN prefix
- Update dashboard, engine, and CLI components for fusion/ branch paths
- Add changeset documenting the breaking change for users

.changeset/rename-task-prefix-branch.md

@@ -0,0 +1,8 @@
+---
+"@gsxdsm/fusion": minor
+"@fusion/core": minor
+"@fusion/dashboard": minor
+"@fusion/engine": minor
+---
+
+Rename default task ID prefix from KB to FN and branch naming from kb/ to fusion/

packages/cli/src/__tests__/extension.test.ts

@@ -153,7 +153,7 @@ describe("kb pi extension", () => {
 
       expect(result.details.taskId).toBe("FN-002");
       expect(result.details.dependencies).toEqual(["FN-001"]);
-      expect(result.content[0].text).toContain("Dependencies: KB-001");
+      expect(result.content[0].text).toContain("Dependencies: FN-001");
     });
   });
 
@@ -315,7 +315,7 @@ describe("kb pi extension", () => {
         makeCtx(tmpDir),
       );
 
-      expect(result.content[0].text).toContain("Attached to KB-001");
+      expect(result.content[0].text).toContain("Attached to FN-001");
       expect(result.content[0].text).toContain("test.txt");
       expect(result.details.attachment).toBeDefined();
       expect(result.details.attachment.originalName).toBe("test.txt");
@@ -366,7 +366,7 @@ describe("kb pi extension", () => {
         undefined,
         makeCtx(tmpDir),
       );
-      expect(pauseResult.content[0].text).toContain("Paused KB-001");
+      expect(pauseResult.content[0].text).toContain("Paused FN-001");
 
       // Verify it's paused
       const showTool = api.tools.get("kb_task_show")!;
@@ -388,7 +388,7 @@ describe("kb pi extension", () => {
         undefined,
         makeCtx(tmpDir),
       );
-      expect(unpauseResult.content[0].text).toContain("Unpaused KB-001");
+      expect(unpauseResult.content[0].text).toContain("Unpaused FN-001");
     });
   });
 });

packages/cli/src/__tests__/task-steer.test.ts

@@ -66,7 +66,7 @@ describe("runTaskSteer", () => {
 
     expect(mockAddSteeringComment).toHaveBeenCalledWith("FN-001", "Focus on error handling", "user");
     expect(mockConsoleLog).toHaveBeenCalledWith(
-      expect.stringContaining("Steering comment added to KB-001")
+      expect.stringContaining("Steering comment added to FN-001")
     );
   });
 

packages/cli/src/commands/task.test.ts

@@ -942,7 +942,7 @@ describe("runTaskRefine", () => {
 
     mockRefineTask = vi.fn().mockResolvedValue({
       id: "FN-002",
-      description: "Refinement of KB-001",
+      description: "Refinement of FN-001",
       column: "triage",
       dependencies: ["FN-001"],
       steps: [],
@@ -1132,7 +1132,7 @@ describe("runTaskDelete", () => {
     await runTaskDelete("FN-001", false);
 
     expect(mockRlQuestion).toHaveBeenCalledOnce();
-    expect(mockRlQuestion).toHaveBeenCalledWith("Are you sure you want to delete KB-001? [y/N] ");
+    expect(mockRlQuestion).toHaveBeenCalledWith("Are you sure you want to delete FN-001? [y/N] ");
     expect(mockRlClose).toHaveBeenCalled();
     expect(mockDeleteTask).toHaveBeenCalledOnce();
     expect(mockDeleteTask).toHaveBeenCalledWith("FN-001");
@@ -1227,7 +1227,7 @@ describe("runTaskComment", () => {
 
     const store = (TaskStore as unknown as ReturnType<typeof vi.fn>).mock.results.at(-1)?.value;
     expect(store.addTaskComment).toHaveBeenCalledWith("FN-001", "Hello", "alice");
-    expect(logSpy).toHaveBeenCalledWith("  ✓ Comment added to KB-001");
+    expect(logSpy).toHaveBeenCalledWith("  ✓ Comment added to FN-001");
   });
 
   it("lists task comments", async () => {
@@ -1309,7 +1309,7 @@ describe("runTaskRetry", () => {
       column: "in-progress"
     }));
 
-    await expect(runTaskRetry("FN-001")).rejects.toThrow("Task KB-001 is not failed (status: none)");
+    await expect(runTaskRetry("FN-001")).rejects.toThrow("Task FN-001 is not failed (status: none)");
   });
 
   it("throws error with correct status when task has different status", async () => {
@@ -1319,7 +1319,7 @@ describe("runTaskRetry", () => {
       column: "in-progress"
     }));
 
-    await expect(runTaskRetry("FN-001")).rejects.toThrow("Task KB-001 is not failed (status: paused)");
+    await expect(runTaskRetry("FN-001")).rejects.toThrow("Task FN-001 is not failed (status: paused)");
   });
 });
 
@@ -1434,7 +1434,7 @@ describe("runTaskLogs", () => {
 
     await runTaskLogs("FN-001");
 
-    expect(logSpy).toHaveBeenCalledWith("No agent logs found for KB-001");
+    expect(logSpy).toHaveBeenCalledWith("No agent logs found for FN-001");
   });
 
   it("exits with error when task not found", async () => {
@@ -1937,7 +1937,7 @@ describe("runTaskPrCreate", () => {
   it("exits with error when branch has no commits", async () => {
     const task = makeInReviewTask();
     mockGetTask.mockResolvedValueOnce(task);
-    mockCreatePr.mockRejectedValueOnce(new Error("No commits between main and kb/kb-001"));
+    mockCreatePr.mockRejectedValueOnce(new Error("No commits between main and fusion/fn-001"));
     
     const exitSpy = vi.spyOn(process, "exit").mockImplementation((() => {
       throw new Error("process.exit");

packages/core/src/db.test.ts

@@ -1,5 +1,6 @@
 import { describe, it, expect, beforeEach, afterEach } from "vitest";
 import { Database, createDatabase, toJson, toJsonNullable, fromJson } from "./db.js";
+import { DEFAULT_PROJECT_SETTINGS } from "./types.js";
 import { mkdtempSync, existsSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
@@ -99,7 +100,7 @@ describe("Database", () => {
       expect(row).toBeDefined();
       expect(row.nextId).toBe(1);
       expect(row.nextWorkflowStepId).toBe(1);
-      expect(row.settings).toBe("{}");
+      expect(row.settings).toBe(JSON.stringify(DEFAULT_PROJECT_SETTINGS));
       expect(row.workflowSteps).toBe("[]");
       expect(row.updatedAt).toBeTruthy();
       // updatedAt should be a valid ISO timestamp

packages/core/src/db.ts

@@ -11,6 +11,7 @@
 import { DatabaseSync } from "node:sqlite";
 import { join } from "node:path";
 import { mkdirSync, existsSync } from "node:fs";
+import { DEFAULT_PROJECT_SETTINGS } from "./types.js";
 
 // ── Types ────────────────────────────────────────────────────────────
 
@@ -283,10 +284,10 @@ export class Database {
     // Run schema migrations
     this.migrate();
 
-    // Seed config row idempotently
+    // Seed config row idempotently with default settings
     const configNow = new Date().toISOString();
     this.db.exec(
-      `INSERT OR IGNORE INTO config (id, nextId, nextWorkflowStepId, settings, workflowSteps, updatedAt) VALUES (1, 1, 1, '{}', '[]', '${configNow}')`,
+      `INSERT OR IGNORE INTO config (id, nextId, nextWorkflowStepId, settings, workflowSteps, updatedAt) VALUES (1, 1, 1, '${JSON.stringify(DEFAULT_PROJECT_SETTINGS)}', '[]', '${configNow}')`,
     );
   }
 

packages/core/src/types.ts

@@ -696,7 +696,7 @@ export const DEFAULT_PROJECT_SETTINGS: ProjectSettings = {
   worktreeInitCommand: undefined,
   recycleWorktrees: false,
   worktreeNaming: "random",
-  taskPrefix: undefined,
+  taskPrefix: "FN",
   includeTaskIdInCommit: true,
   planningProvider: undefined,
   planningModelId: undefined,

packages/dashboard/app/components/SettingsModal.tsx

@@ -454,7 +454,7 @@ export function SettingsModal({
               <input
                 id="taskPrefix"
                 type="text"
-                placeholder="KB"
+                placeholder="FN"
                 value={form.taskPrefix || ""}
                 onChange={(e) => {
                   const val = e.target.value;

packages/dashboard/app/components/__tests__/MergeDetails.test.tsx

@@ -32,7 +32,7 @@ describe("MergeDetails", () => {
             deletions: 2,
             mergedAt: "2026-01-01T01:00:00.000Z",
             prNumber: 42,
-            mergeCommitMessage: "feat(KB-001): merge kb/kb-001",
+            mergeCommitMessage: "feat(FN-001): merge fusion/fn-001",
             mergeConfirmed: true,
           },
         })}
@@ -44,7 +44,7 @@ describe("MergeDetails", () => {
     expect(screen.getByText("5")).toBeTruthy();
     expect(screen.getByText("+10 / -2")).toBeTruthy();
     expect(screen.getByText("#42")).toBeTruthy();
-    expect(screen.getByText("feat(KB-001): merge kb/kb-001")).toBeTruthy();
+    expect(screen.getByText("feat(FN-001): merge fusion/fn-001")).toBeTruthy();
     expect(screen.getByText("Merged successfully")).toBeTruthy();
   });
 });

packages/engine/src/worktree-pool.test.ts

@@ -156,7 +156,7 @@ describe("WorktreePool", () => {
         (c) => typeof c[0] === "string" && (c[0] as string).includes("checkout -B"),
       );
       expect(checkoutCall).toBeDefined();
-      expect(checkoutCall![0]).toBe('git checkout -B "fusion/fn-042" kb/kb-041');
+      expect(checkoutCall![0]).toBe('git checkout -B "fusion/fn-042" fusion/fn-041');
     });
 
     it("tolerates git checkout -- . failure (already clean)", () => {