feat: set up Supabase branching with seed data

Add seed.sql to create test auth user and sample data for preview
branches. Use extensions.crypt() for password hashing. Remove
health_timeout from config.toml (unsupported by branching CLI).

Configuration: GitHub integration "Supabase directory" must be set
to "." (not "supabase") for correct seed path resolution.

Test credentials: test@example.com / test00

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jasoncrawford

supabase/config.toml

@@ -29,8 +29,6 @@ enabled = false
 port = 54322
 # Port used by db diff command to initialize the shadow database.
 shadow_port = 54320
-# Maximum amount of time to wait for health check when starting the local database.
-health_timeout = "2m"
 # The database major version to use. This has to be the same as your remote database's. Run `SHOW
 # server_version;` on the remote database to check.
 major_version = 17

supabase/seed.sql

@@ -0,0 +1,77 @@
+-- Seed data for Supabase branch databases (preview deploys)
+-- This file runs automatically when a branch DB is created via Supabase Branching.
+
+-- ============================================================================
+-- Test auth user: test@example.com / test00
+-- ============================================================================
+
+INSERT INTO auth.users (
+  id,
+  instance_id,
+  aud,
+  role,
+  email,
+  encrypted_password,
+  email_confirmed_at,
+  last_sign_in_at,
+  raw_app_meta_data,
+  raw_user_meta_data,
+  created_at,
+  updated_at,
+  confirmation_token,
+  email_change,
+  email_change_token_new,
+  recovery_token
+) VALUES (
+  'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+  '00000000-0000-0000-0000-000000000000',
+  'authenticated',
+  'authenticated',
+  'test@example.com',
+  extensions.crypt('test00', extensions.gen_salt('bf')),
+  now(),
+  now(),
+  '{"provider": "email", "providers": ["email"]}',
+  '{}',
+  now(),
+  now(),
+  '',
+  '',
+  '',
+  ''
+);
+
+INSERT INTO auth.identities (
+  id,
+  user_id,
+  identity_data,
+  provider,
+  provider_id,
+  last_sign_in_at,
+  created_at,
+  updated_at
+) VALUES (
+  'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+  'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+  '{"sub": "a1b2c3d4-e5f6-7890-abcd-ef1234567890", "email": "test@example.com"}',
+  'email',
+  'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
+  now(),
+  now(),
+  now()
+);
+
+-- ============================================================================
+-- Sample sites
+-- ============================================================================
+
+INSERT INTO sites (id, name, url) VALUES
+  ('11111111-1111-1111-1111-111111111111', 'Example Site', 'https://example.com'),
+  ('22222222-2222-2222-2222-222222222222', 'Anthropic', 'https://www.anthropic.com');
+
+-- ============================================================================
+-- Test contact
+-- ============================================================================
+
+INSERT INTO contacts (email) VALUES
+  ('test@example.com');