Multi-account support and streaming fixes

- Change LinkedAccount unique constraint to (userId, serviceId, accountId)
- Add linkedAccountId to StreamDestination for per-account targeting
- OAuth callbacks upsert by accountId so different accounts create new rows
- Delete endpoint changed to /providers/accounts/:id
- getDecryptedToken resolves tokens by linkedAccountId instead of serviceId
- /start transition wrapped in try-catch (enableAutoStart compatibility)
- /end always attempts YouTube complete transition regardless of plan status
- autoDetectEndedPlans loads tokens per-destination

src/routes/providers/accounts.ts

@@ -26,27 +26,23 @@ const accountRoutes: FastifyPluginAsync = async (fastify) => {
     return response;
   });
 
-  // DELETE /providers/:serviceId — revoke tokens and unlink
-  fastify.delete<{ Params: { serviceId: string } }>('/providers/:serviceId', {
+  // DELETE /providers/accounts/:id — revoke tokens and unlink by account ID
+  fastify.delete<{ Params: { id: string } }>('/providers/accounts/:id', {
     preHandler: [requireAuth],
     schema: {
       params: {
         type: 'object',
-        required: ['serviceId'],
+        required: ['id'],
         properties: {
-          serviceId: { type: 'string', enum: ['YOUTUBE', 'TWITCH'] },
+          id: { type: 'string' },
         },
       },
     },
   }, async (request, reply) => {
-    const { serviceId } = request.params;
-
-    const account = await fastify.prisma.linkedAccount.findUnique({
+    const account = await fastify.prisma.linkedAccount.findFirst({
       where: {
-        userId_serviceId: {
-          userId: request.userId,
-          serviceId,
-        },
+        id: request.params.id,
+        userId: request.userId,
       },
     });
 
@@ -57,7 +53,7 @@ const accountRoutes: FastifyPluginAsync = async (fastify) => {
     // Best-effort revoke tokens at the provider
     try {
       const accessToken = decrypt(account.accessTokenEnc, account.accessTokenIv);
-      if (serviceId === 'YOUTUBE') {
+      if (account.serviceId === 'YOUTUBE') {
         await revokeYouTubeToken(accessToken);
       } else {
         await revokeTwitchToken(accessToken);