feat: production deployment - full update with providers, admin, glossaries, pricing, tests

Major changes across backend, frontend, infrastructure:
- Provider system with model selection (Google, DeepL, OpenAI, Ollama, Google Cloud)
- Admin panel: user management, pricing, settings
- Glossary system with CSV import/export
- Subscription and tier quota management
- Security hardening (rate limiting, API key auth, path traversal fixes)
- Docker compose for dev, prod, and IONOS deployment
- Alembic migrations for new tables
- Frontend: dashboard, pricing page, landing page, i18n (en/fr)
- Test suite and verification scripts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/test_file_handler.py

@@ -0,0 +1,67 @@
+import os
+import hashlib
+import pytest
+from pathlib import Path
+from utils.file_handler import file_handler, FileHandler
+
+
+def test_calculate_sha256(tmp_path):
+    test_file = tmp_path / "test.txt"
+    content = b"Hello, BMAD!"
+    test_file.write_bytes(content)
+
+    expected_hash = hashlib.sha256(content).hexdigest()
+    actual_hash = file_handler.calculate_sha256(test_file)
+
+    assert actual_hash == expected_hash
+
+
+def test_calculate_sha256_nonexistent_file(tmp_path):
+    nonexistent = tmp_path / "does_not_exist.txt"
+    result = file_handler.calculate_sha256(nonexistent)
+    assert result is None
+
+
+def test_calculate_sha256_large_file(tmp_path):
+    test_file = tmp_path / "large.bin"
+    content = os.urandom(1024 * 1024)
+    test_file.write_bytes(content)
+
+    expected_hash = hashlib.sha256(content).hexdigest()
+    actual_hash = file_handler.calculate_sha256(test_file)
+
+    assert actual_hash == expected_hash
+
+
+def test_get_file_info_with_hash(tmp_path):
+    test_file = tmp_path / "test.txt"
+    content = b"Metadata test"
+    test_file.write_bytes(content)
+
+    expected_hash = hashlib.sha256(content).hexdigest()
+    info = file_handler.get_file_info(test_file)
+
+    assert "sha256" in info
+    assert info["sha256"] == expected_hash
+    assert info["filename"] == "test.txt"
+    assert info["size_bytes"] == len(content)
+
+
+def test_get_file_info_nonexistent(tmp_path):
+    nonexistent = tmp_path / "does_not_exist.txt"
+    info = file_handler.get_file_info(nonexistent)
+    assert info == {}
+
+
+def test_cleanup_file_success(tmp_path, caplog):
+    test_file = tmp_path / "to_delete.txt"
+    test_file.write_bytes(b"delete me")
+
+    assert test_file.exists()
+    file_handler.cleanup_file(test_file)
+    assert not test_file.exists()
+
+
+def test_cleanup_file_nonexistent(tmp_path, caplog):
+    nonexistent = tmp_path / "does_not_exist.txt"
+    file_handler.cleanup_file(nonexistent)