feat(db): add oauth_accounts table to schema v5 (2 new tests)

UNIQUE(provider, twitch_user_id), indices on provider + is_default.
108 unit tests gruen.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/main/infra/db.test.ts

@@ -72,6 +72,38 @@ describe('openDatabase', () => {
         expect(c?.c).toBe(2);
     });
 
+    test('oauth_accounts table exists and accepts insert', () => {
+        db = openDatabase(path.join(tmpDir, 'oauth.db'));
+        db.run(
+            `INSERT INTO oauth_accounts(provider, twitch_user_id, login, encrypted_access_token)
+             VALUES (?, ?, ?, ?)`,
+            ['twitch', 'user-123', 'alice', 'ciphertext-blob']
+        );
+        const row = db.get<{ login: string; provider: string }>(
+            'SELECT login, provider FROM oauth_accounts WHERE twitch_user_id = ?',
+            ['user-123']
+        );
+        expect(row?.login).toBe('alice');
+        expect(row?.provider).toBe('twitch');
+    });
+
+    test('oauth_accounts UNIQUE(provider, twitch_user_id) enforced', () => {
+        db = openDatabase(path.join(tmpDir, 'oauth-unique.db'));
+        db.run(
+            `INSERT INTO oauth_accounts(provider, twitch_user_id, login, encrypted_access_token)
+             VALUES (?, ?, ?, ?)`,
+            ['twitch', 'u1', 'a', 'x']
+        );
+        const handle = db;
+        expect(() => {
+            handle.run(
+                `INSERT INTO oauth_accounts(provider, twitch_user_id, login, encrypted_access_token)
+                 VALUES (?, ?, ?, ?)`,
+                ['twitch', 'u1', 'b', 'y']
+            );
+        }).toThrow();
+    });
+
     test('transaction rolls back on throw', () => {
         db = openDatabase(path.join(tmpDir, 'g.db'));
         const handle = db;

src/main/infra/schema-v5.ts

@@ -64,6 +64,25 @@ CREATE TABLE IF NOT EXISTS archive_files (
 
 CREATE INDEX IF NOT EXISTS idx_archive_streamer ON archive_files(streamer_login);
 
+CREATE TABLE IF NOT EXISTS oauth_accounts (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    provider TEXT NOT NULL,
+    twitch_user_id TEXT,
+    login TEXT,
+    display_name TEXT,
+    encrypted_access_token TEXT NOT NULL,
+    encrypted_refresh_token TEXT,
+    expires_at INTEGER,
+    scopes_json TEXT,
+    is_default INTEGER NOT NULL DEFAULT 0,
+    created_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),
+    updated_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),
+    UNIQUE(provider, twitch_user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_oauth_provider ON oauth_accounts(provider);
+CREATE INDEX IF NOT EXISTS idx_oauth_default ON oauth_accounts(is_default);
+
 CREATE TABLE IF NOT EXISTS migrations_applied (
     name TEXT PRIMARY KEY,
     applied_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),