feat(phase1): add image storage utilities

- Create backend/services/image_storage.py with 4 core functions:
  - sanitize_filename(): remove unsafe chars, limit to 255 chars, convert to lowercase
  - get_unique_filename(): handle collisions with UUID suffix (format: {name}_{uuid8}_{variant}.jpg)
  - ensure_image_directories(): create /images/ root and category subdirs on startup
  - save_image(): save bytes to /images/{category}/{filename}, returns relative path
- Create comprehensive test suite (22 tests) covering all functionality
- Integrate ensure_image_directories() into FastAPI startup event
- Directory structure: /images/{category}/{filename}
- Collision handling: auto-suffix with UUID if filename exists
- All tests passing, pathlib.Path for safe operations

venv/lib/python3.12/site-packages/pygments/lexers/compiled.py

@@ -0,0 +1,35 @@
+"""
+    pygments.lexers.compiled
+    ~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Just export lexer classes previously contained in this module.
+
+    :copyright: Copyright 2006-present by the Pygments team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+# ruff: noqa: F401
+from pygments.lexers.jvm import JavaLexer, ScalaLexer
+from pygments.lexers.c_cpp import CLexer, CppLexer
+from pygments.lexers.d import DLexer
+from pygments.lexers.objective import ObjectiveCLexer, \
+    ObjectiveCppLexer, LogosLexer
+from pygments.lexers.go import GoLexer
+from pygments.lexers.rust import RustLexer
+from pygments.lexers.c_like import ECLexer, ValaLexer, CudaLexer
+from pygments.lexers.pascal import DelphiLexer, PortugolLexer, Modula2Lexer
+from pygments.lexers.ada import AdaLexer
+from pygments.lexers.business import CobolLexer, CobolFreeformatLexer
+from pygments.lexers.fortran import FortranLexer
+from pygments.lexers.prolog import PrologLexer
+from pygments.lexers.python import CythonLexer
+from pygments.lexers.graphics import GLShaderLexer
+from pygments.lexers.ml import OcamlLexer
+from pygments.lexers.basic import BlitzBasicLexer, BlitzMaxLexer, MonkeyLexer
+from pygments.lexers.dylan import DylanLexer, DylanLidLexer, DylanConsoleLexer
+from pygments.lexers.ooc import OocLexer
+from pygments.lexers.felix import FelixLexer
+from pygments.lexers.nimrod import NimrodLexer
+from pygments.lexers.crystal import CrystalLexer
+
+__all__ = []