feat: Implement end-to-end encrypted chat with new API routes, crypto utilities, and UI components.

src/db/schema.ts

@@ -955,6 +955,103 @@ export const chatMessagesRelations = relations(chatMessages, ({ one }) => ({
   }),
 }));
 
+/**
+ * V2.1 E2EE: Device Bundles
+ * Stores the identity and signed prekeys for each user device.
+ * Verified by the root ECDSA identity key (signature).
+ */
+export const chatDeviceBundles = pgTable('chat_device_bundles', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
+  did: text('did').notNull(),
+
+  // The device identifier (UUID generated by client)
+  deviceId: text('device_id').notNull(),
+
+  // X25519 Identity Key (Base64)
+  identityKey: text('identity_key').notNull(),
+
+  // Signed PreKey (JSON: { id, key, sig })
+  signedPreKey: text('signed_pre_key').notNull(),
+
+  // One-Time Keys (JSON array of { id, key }) - cached/uploaded batch
+  // Note: Individual keys are usually stored in a separate table for atomic consumption,
+  // but initial upload can be here or we strictly use chat_one_time_keys.
+  // We will use the separate table for consumption tracking.
+
+  // The ECDSA signature covering (did, deviceId, identityKey, signedPreKey)
+  // Signed by the user's Root Identity Key (P-256)
+  signature: text('signature').notNull(),
+
+  lastSeenAt: timestamp('last_seen_at').defaultNow().notNull(),
+  createdAt: timestamp('created_at').defaultNow().notNull(),
+}, (table) => [
+  index('chat_bundles_user_idx').on(table.userId),
+  index('chat_bundles_did_idx').on(table.did),
+  // compound index for fast lookup of a specific device
+  uniqueIndex('chat_bundles_device_unique').on(table.userId, table.deviceId),
+]);
+
+export const chatDeviceBundlesRelations = relations(chatDeviceBundles, ({ one, many }) => ({
+  user: one(users, {
+    fields: [chatDeviceBundles.userId],
+    references: [users.id],
+  }),
+  oneTimeKeys: many(chatOneTimeKeys),
+}));
+
+/**
+ * V2.1 E2EE: One-Time Prekeys
+ * Pool of disposable keys for X3DH.
+ */
+export const chatOneTimeKeys = pgTable('chat_one_time_keys', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
+  bundleId: uuid('bundle_id').notNull().references(() => chatDeviceBundles.id, { onDelete: 'cascade' }),
+
+  keyId: integer('key_id').notNull(),
+  publicKey: text('public_key').notNull(), // X25519 Base64
+
+  createdAt: timestamp('created_at').defaultNow().notNull(),
+}, (table) => [
+  index('chat_otk_bundle_idx').on(table.bundleId),
+  // Ensure (bundleId, keyId) is unique
+  uniqueIndex('chat_otk_unique').on(table.bundleId, table.keyId),
+]);
+
+export const chatOneTimeKeysRelations = relations(chatOneTimeKeys, ({ one }) => ({
+  bundle: one(chatDeviceBundles, {
+    fields: [chatOneTimeKeys.bundleId],
+    references: [chatDeviceBundles.id],
+  }),
+}));
+
+/**
+ * V2.1 E2EE: Chat Inbox
+ * Stores encrypted envelopes waiting for delivery to a specific device.
+ */
+export const chatInbox = pgTable('chat_inbox', {
+  id: uuid('id').primaryKey().defaultRandom(),
+
+  // Recipient info
+  recipientDid: text('recipient_did').notNull(),
+  recipientDeviceId: text('recipient_device_id'), // Null means "all devices" or "not yet routed"
+
+  // Sender info
+  senderDid: text('sender_did').notNull(),
+
+  // The Envelope (SignedAction format)
+  // Contains: { action: "chat.deliver", did, handle, ts, nonce, data: { ciphertext, header... }, sig }
+  envelope: text('envelope_json').notNull(),
+
+  isRead: boolean('is_read').default(false).notNull(),
+  createdAt: timestamp('created_at').defaultNow().notNull(),
+  expiresAt: timestamp('expires_at').notNull(), // TTL (e.g. 30 days)
+}, (table) => [
+  index('chat_inbox_recipient_idx').on(table.recipientDid, table.recipientDeviceId),
+  index('chat_inbox_created_idx').on(table.createdAt),
+]);
+
 /**
  * Typing indicators for real-time chat UX.
  * Short-lived records that expire after 10 seconds.