Add server deployment support with Essentia

- Add install-server.sh for easy deployment on Linux servers
- Update Dockerfile to auto-detect architecture (x86_64/ARM64)
- Add deploy.sh for remote deployment
- Update requirements.txt with Essentia support notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/src/alembic/versions/20251127_002_rename_metadata.py

@@ -0,0 +1,37 @@
+"""Rename metadata to extra_metadata
+
+Revision ID: 002
+Revises: 001
+Create Date: 2025-11-27
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = '002'
+down_revision: Union[str, None] = '001'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Check if column exists before renaming
+    op.execute("""
+        DO $$
+        BEGIN
+            IF EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name='audio_tracks' AND column_name='metadata'
+            ) THEN
+                ALTER TABLE audio_tracks RENAME COLUMN metadata TO extra_metadata;
+            END IF;
+        END $$;
+    """)
+
+
+def downgrade() -> None:
+    # Rename back to metadata
+    op.execute('ALTER TABLE audio_tracks RENAME COLUMN extra_metadata TO metadata')