feat: M3 import & indexing engine delivery layer with durable collision handling, space checking and console

dev.ps1

@@ -23,12 +23,21 @@ try {
         { $_ -in 'test', 'lint' } {
             $ComposeArgs = @('run', '--rm', '--no-deps', '-T', '--entrypoint', 'composer', 'app', $Command)
         }
+        { $_ -in 'import', 'worker-once' } {
+            $ComposeArgs = @('run', '--rm', '-T', '--entrypoint', 'php', 'app', 'bin/meshvault', $Command)
+        }
+        'worker' {
+            # Interactive so Ctrl+C reaches the worker's graceful-stop handler.
+            $ComposeArgs = @('run', '--rm', '--entrypoint', 'php', 'app', 'bin/meshvault', 'worker')
+        }
         'assets' { $ComposeArgs = @('run', '--rm', '--no-deps', '-T', 'assets', 'npm', 'run', 'build', '--') }
         { $_ -in 'watch', 'assets:watch' } {
             $ComposeArgs = @('run', '--rm', '--no-deps', '-T', 'assets', 'npm', 'run', 'watch', '--')
         }
         default {
-            [Console]::Error.WriteLine('Usage: dev.ps1 up|down|test|lint|assets|watch|migrate|seed [arguments]')
+            [Console]::Error.WriteLine(
+                'Usage: dev.ps1 up|down|test|lint|assets|watch|migrate|seed|import|worker|worker-once [arguments]'
+            )
             exit 2
         }
     }