feat(FN-4743): complete Step 1 — add mail cleanup project setting

Fusion-Task-Id: FN-4743
Fusion-Task-Lineage: 50d1d8e4-66d5-4299-843b-28072a904277

packages/core/src/__tests__/settings-parity.test.ts

@@ -96,6 +96,13 @@ describe("settings key parity", () => {
     expect(isGlobalSettingsKey("chatAutoCleanupDays")).toBe(false);
   });
 
+  it("defaults mailAutoCleanupDays to off and keeps it project-scoped", () => {
+    expect(DEFAULT_PROJECT_SETTINGS.mailAutoCleanupDays).toBe(0);
+    expect(isProjectSettingsKey("mailAutoCleanupDays")).toBe(true);
+    expect(isGlobalSettingsKey("mailAutoCleanupDays")).toBe(false);
+    expect(PROJECT_SETTINGS_KEYS).toContain("mailAutoCleanupDays");
+  });
+
   it("keeps heartbeatScopeDiscipline project-scoped with strict default", () => {
     expect(DEFAULT_PROJECT_SETTINGS.heartbeatScopeDiscipline).toBe("strict");
     expect(isProjectSettingsKey("heartbeatScopeDiscipline")).toBe(true);

packages/core/src/settings-schema.ts

@@ -348,6 +348,7 @@ export const DEFAULT_PROJECT_SETTINGS = {
   reviewHandoffPolicy: "disabled",
   showQuickChatFAB: false,
   chatAutoCleanupDays: 0,
+  mailAutoCleanupDays: 0,
   chatRoomRecentVerbatimMessages: 12,
   chatRoomCompactionFetchLimit: 80,
   chatRoomSummaryMaxChars: 1_500,

packages/core/src/types.ts

@@ -3030,6 +3030,9 @@ export interface ProjectSettings {
   /** Number of days of chat inactivity before old chat sessions/rooms are auto-cleaned.
    *  Allowed values: 0 (off, default), 7, 14, 30, 60, 90. Uses updatedAt inactivity age. */
   chatAutoCleanupDays?: number;
+  /** Number of days of inactivity before old inbox/outbox messages are auto-pruned.
+   *  Allowed values: 0 (off, default) or one of 7 | 14 | 30 | 60 | 90. Uses messages.updatedAt inactivity age. */
+  mailAutoCleanupDays?: number;
   /** Number of most-recent chat-room messages kept verbatim in the responder transcript.
    *  Older messages are compacted into a summary block. Default: 12. */
   chatRoomRecentVerbatimMessages?: number;