fix(FN-680): restore TaskStore project resolution and fresh schema writes

- fix TaskStore.getOrCreateForProject to resolve projects through BackwardCompat and support legacy .fusion/.kb detection
- add regression tests for exact-name project lookup, legacy cwd fallback, and fresh-schema task create/update persistence
- sync the tasks schema definition with missionId support so fresh databases match runtime migrations
- add project overview and selector styles for the multi-project dashboard UI

packages/core/src/__tests__/store-backward-compat.test.ts

@@ -1,5 +1,6 @@
 import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
-import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from "node:fs";
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync, existsSync } from "node:fs";
+import { DatabaseSync } from "node:sqlite";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { TaskStore } from "../store.js";
@@ -10,10 +11,13 @@ function createTempDir(): string {
   return mkdtempSync(join(tmpdir(), "kb-compat-test-"));
 }
 
-// Helper to create a fake kb project structure
-function createFakeKbProject(dir: string): void {
-  mkdirSync(join(dir, ".kb"), { recursive: true });
-  writeFileSync(join(dir, ".kb", "kb.db"), "");
+// Helper to create a fake fusion project structure for the current store implementation
+function createFakeFusionProject(dir: string): void {
+  const fusionDir = join(dir, ".fusion");
+  mkdirSync(fusionDir, { recursive: true });
+  const db = new DatabaseSync(join(fusionDir, "kb.db"));
+  db.exec("CREATE TABLE IF NOT EXISTS sanity (id INTEGER PRIMARY KEY)");
+  db.close();
 }
 
 describe("TaskStore Backward Compatibility", () => {
@@ -58,7 +62,7 @@ describe("TaskStore Backward Compatibility", () => {
       expect(settings).toBeDefined();
     });
 
-    it("should find project by name when ID not found", async () => {
+    it("should fall back to exact project name lookup when ID lookup misses", async () => {
       const projectDir = join(tempDir, "my-project");
       mkdirSync(projectDir, { recursive: true });
 
@@ -115,13 +119,24 @@ describe("TaskStore Backward Compatibility", () => {
     });
 
 
-    it("should fall back to legacy mode when no projects registered", async () => {
-      // No projects registered in central core
-      process.chdir(tempDir);
+    it("should fall back to process.cwd() legacy mode against the current .fusion path", async () => {
+      const projectDir = join(tempDir, "legacy-project");
+      mkdirSync(projectDir, { recursive: true });
+      createFakeFusionProject(projectDir);
+      process.chdir(projectDir);
+
+      const centralDb = join(tempDir, "kb-central.db");
+      await centralCore.close();
+      rmSync(centralDb, { force: true });
+      centralCore = new CentralCore(tempDir);
 
       const store = await TaskStore.getOrCreateForProject(undefined, centralCore);
 
       expect(store).toBeInstanceOf(TaskStore);
+      const task = await store.createTask({ description: "legacy task" });
+      expect(task.id).toBe("FN-001");
+      expect(existsSync(join(projectDir, ".fusion", "kb.db"))).toBe(true);
+      expect(existsSync(join(projectDir, ".fusion", "tasks", task.id, "task.json"))).toBe(true);
     });
 
     it("should throw when project ID not found", async () => {
@@ -130,6 +145,20 @@ describe("TaskStore Backward Compatibility", () => {
       ).rejects.toThrow('Project "non-existent-project" not found');
     });
 
+    it("should find project by exact registered name", async () => {
+      const projectDir = join(tempDir, "Casey");
+      mkdirSync(projectDir, { recursive: true });
+
+      await centralCore.registerProject({
+        name: "Casey",
+        path: projectDir,
+        isolationMode: "in-process",
+      });
+
+      const store = await TaskStore.getOrCreateForProject("Casey", centralCore);
+      expect(store).toBeInstanceOf(TaskStore);
+    });
+
     it("should auto-initialize central core if not provided", async () => {
       const projectDir = join(tempDir, "my-project");
       mkdirSync(projectDir, { recursive: true });