feat(FN-5284): surface db corruption via health checks, self-healing, and d

- fix(FN-5284): add db corruption audit mutation type
- feat(FN-5284): complete Step 7 — document corruption surfacing
- feat(FN-5284): complete Step 6 — add db corruption banner
- feat(FN-5284): complete Step 5 — extend health payload
- feat(FN-5284): complete Step 3 — surface db corruption in self-healing
- feat(FN-5284): complete Step 2 — add db corruption notification event
- feat(FN-5284): complete Step 1 — expose integrity check errors

Fusion-Task-Id: FN-5284

packages/core/src/__tests__/db.test.ts

@@ -465,6 +465,8 @@ describe("Database", () => {
         expect(dbB.integrityCheckLastRunAt).toBeTruthy();
         expect(dbA.corruptionDetected).toBe(false);
         expect(dbB.corruptionDetected).toBe(false);
+        expect(dbA.integrityCheckErrors).toEqual([]);
+        expect(dbB.integrityCheckErrors).toEqual([]);
       } finally {
         dbA.close();
         dbB.close();
@@ -478,7 +480,7 @@ describe("Database", () => {
       vi.useFakeTimers();
       const integritySpy = vi.spyOn(Database.prototype, "integrityCheck").mockReturnValue({
         ok: false,
-        errors: ["malformed database"],
+        errors: ["malformed database", "broken index"],
       });
       const freshDir = makeTmpDir();
       const freshFusionDir = join(freshDir, ".fusion");
@@ -498,6 +500,8 @@ describe("Database", () => {
         expect(dbB.integrityCheckLastRunAt).toBeTruthy();
         expect(dbA.corruptionDetected).toBe(true);
         expect(dbB.corruptionDetected).toBe(true);
+        expect(dbA.integrityCheckErrors).toEqual(["malformed database", "broken index"]);
+        expect(dbB.integrityCheckErrors).toEqual(["malformed database", "broken index"]);
       } finally {
         dbA.close();
         dbB.close();
@@ -1036,6 +1040,7 @@ describe("Database", () => {
     it("returns ok for healthy databases and leaves corruption flag false", () => {
       expect(db.corruptionDetected).toBe(false);
       expect(db.integrityCheck()).toEqual({ ok: true });
+      expect(db.integrityCheckErrors).toEqual([]);
     });
 
     it("keeps corruptionDetected false after init for healthy database", () => {

packages/core/src/__tests__/store-health.test.ts

@@ -16,6 +16,8 @@ describe("TaskStore.getDatabaseHealth", () => {
     const health = store.getDatabaseHealth();
 
     expect(health.healthy).toBe(true);
+    expect(health.corruptionDetected).toBe(false);
+    expect(health.corruptionErrors).toEqual([]);
     expect(health.isRunning).toBe(false);
     expect(health.lastCheckedAt).toBeNull();
   });
@@ -27,19 +29,34 @@ describe("TaskStore.getDatabaseHealth", () => {
     const health = store.getDatabaseHealth();
 
     expect(health.healthy).toBe(true);
+    expect(health.corruptionDetected).toBe(false);
+    expect(health.corruptionErrors).toEqual([]);
     expect(health.isRunning).toBe(true);
   });
 
   it("reports unhealthy when corruption has been detected", () => {
     const db = store.getDatabase();
     db.corruptionDetected = true;
+    db.integrityCheckErrors = ["bad row", "bad index"];
     db.integrityCheckPending = false;
     db.integrityCheckLastRunAt = "2026-05-11T12:34:56.000Z";
 
     const health = store.getDatabaseHealth();
 
     expect(health.healthy).toBe(false);
+    expect(health.corruptionDetected).toBe(true);
+    expect(health.corruptionErrors).toEqual(["bad row", "bad index"]);
     expect(health.isRunning).toBe(false);
     expect(health.lastCheckedAt?.toISOString()).toBe("2026-05-11T12:34:56.000Z");
   });
+
+  it("caps corruption errors to the first five entries", () => {
+    const db = store.getDatabase();
+    db.corruptionDetected = true;
+    db.integrityCheckErrors = ["one", "two", "three", "four", "five", "six"];
+
+    const health = store.getDatabaseHealth();
+
+    expect(health.corruptionErrors).toEqual(["one", "two", "three", "four", "five"]);
+  });
 });

packages/core/src/db.ts

@@ -1251,6 +1251,7 @@ export class Database {
   /** Returns the database file path (or ":memory:" for in-memory databases). */
   get path(): string { return this.dbPath; }
   corruptionDetected = false;
+  integrityCheckErrors: string[] = [];
   integrityCheckPending = false;
   integrityCheckLastRunAt: string | null = null;
   /** Tracks transaction nesting depth for savepoint-based nested transactions. */
@@ -3684,6 +3685,7 @@ export class Database {
         participant.integrityCheckPending = false;
         participant.integrityCheckLastRunAt = startedAt;
         participant.corruptionDetected = !integrity.ok;
+        participant.integrityCheckErrors = integrity.ok ? [] : [...integrity.errors];
       }
 
       if (!integrity.ok) {

packages/core/src/store.ts

@@ -9329,11 +9329,16 @@ ${stepsSection}`;
 
   getDatabaseHealth(): {
     healthy: boolean;
+    corruptionDetected: boolean;
+    corruptionErrors: string[];
     lastCheckedAt: Date | null;
     isRunning: boolean;
   } {
+    const corruptionDetected = this.db.corruptionDetected;
     return {
-      healthy: !this.db.corruptionDetected,
+      healthy: !corruptionDetected,
+      corruptionDetected,
+      corruptionErrors: this.db.integrityCheckErrors.slice(0, 5),
       lastCheckedAt: this.db.integrityCheckLastRunAt ? new Date(this.db.integrityCheckLastRunAt) : null,
       isRunning: this.db.integrityCheckPending,
     };

packages/core/src/types.ts

@@ -404,6 +404,7 @@ export type NtfyNotificationEvent =
   | "planning-awaiting-input"
   | "gridlock"
   | "board-stall-unrecovered"
+  | "db-corruption-detected"
   | "fallback-used"
   | "memory-dreams-processed"
   | "token-budget"
@@ -422,6 +423,7 @@ export const NOTIFICATION_EVENTS = [
   "planning-awaiting-input",
   "gridlock",
   "board-stall-unrecovered",
+  "db-corruption-detected",
   "fallback-used",
   "memory-dreams-processed",
   "token-budget",