Fix new deployment detection in migration runner

- Check for essential tables (events, photos, admin_users, activity_logs)
  to determine if it's truly a new deployment
- Only run detectExistingSchema() for actual existing deployments
- Remove obsolete init.js references (now 001_init.js)
- Fix migration filters to handle renamed init file

The issue was that detectExistingSchema() was marking migrations as
applied from previous failed runs, causing the system to incorrectly
treat new deployments as existing ones and run legacy migrations that
expect tables to already exist.

backend/migrations/run-migrations-safe.js

@@ -104,15 +104,24 @@ async function runMigrations() {
     // Create migrations tracking table
     await ensureMigrationsTable();
     
-    // Detect and mark existing schema
-    await detectExistingSchema();
+    // Check if essential tables exist to determine if this is truly a new deployment
+    const hasEventsTable = await db.schema.hasTable('events');
+    const hasPhotosTable = await db.schema.hasTable('photos');
+    const hasAdminTable = await db.schema.hasTable('admin_users');
+    const hasActivityLogsTable = await db.schema.hasTable('activity_logs');
     
     // Get applied migrations
     const appliedMigrations = await db('migrations').select('filename');
     const appliedFilenames = appliedMigrations.map(m => m.filename);
     
-    // Check if this is a new deployment (no migrations have been applied)
-    const isNewDeployment = appliedFilenames.length === 0;
+    // Check if this is a new deployment
+    // It's new if no essential tables exist OR no migrations have been applied
+    const isNewDeployment = (!hasEventsTable || !hasPhotosTable || !hasAdminTable || !hasActivityLogsTable) || appliedFilenames.length === 0;
+    
+    // Only detect existing schema for truly existing deployments
+    if (!isNewDeployment) {
+      await detectExistingSchema();
+    }
     
     // Get migration files from appropriate directories
     let migrationFiles = [];
@@ -123,7 +132,7 @@ async function runMigrations() {
       const coreDir = path.join(__dirname, 'core');
       const coreFiles = await fs.readdir(coreDir);
       migrationFiles = coreFiles
-        .filter(f => f.match(/^\d{3}_.*\.js$/) || f === 'init.js')
+        .filter(f => f.match(/^\d{3}_.*\.js$/))
         .map(f => path.join('core', f))
         .sort();
     } else {
@@ -141,7 +150,7 @@ async function runMigrations() {
       const coreDir = path.join(__dirname, 'core');
       const coreFiles = await fs.readdir(coreDir);
       const coreMigrations = coreFiles
-        .filter(f => f.match(/^\d{3}_.*\.js$/) || f === 'init.js')
+        .filter(f => f.match(/^\d{3}_.*\.js$/))
         .map(f => path.join('core', f));
       
       // Combine and sort by number
@@ -149,9 +158,6 @@ async function runMigrations() {
         .sort((a, b) => {
           const baseA = path.basename(a);
           const baseB = path.basename(b);
-          // Ensure init.js runs first
-          if (baseA === 'init.js') return -1;
-          if (baseB === 'init.js') return 1;
           const numA = parseInt(baseA.split('_')[0]);
           const numB = parseInt(baseB.split('_')[0]);
           return numA - numB;