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/styles/fruity.py

@@ -0,0 +1,47 @@
+"""
+    pygments.styles.fruity
+    ~~~~~~~~~~~~~~~~~~~~~~
+
+    pygments version of my "fruity" vim theme.
+
+    :copyright: Copyright 2006-present by the Pygments team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+from pygments.style import Style
+from pygments.token import Token, Comment, Name, Keyword, \
+    Generic, Number, String, Whitespace
+
+
+__all__ = ['FruityStyle']
+
+
+class FruityStyle(Style):
+    """
+    Pygments version of the "native" vim theme.
+    """
+
+    name = 'fruity'
+
+    background_color = '#111111'
+    highlight_color = '#333333'
+
+    styles = {
+        Whitespace:         '#888888',
+        Token:              '#ffffff',
+        Generic.Output:     '#444444 bg:#222222',
+        Keyword:            '#fb660a bold',
+        Keyword.Pseudo:     'nobold',
+        Number:             '#0086f7 bold',
+        Name.Tag:           '#fb660a bold',
+        Name.Variable:      '#fb660a',
+        Comment:            '#008800 bg:#0f140f italic',
+        Name.Attribute:     '#ff0086 bold',
+        String:             '#0086d2',
+        Name.Function:      '#ff0086 bold',
+        Generic.Heading:    '#ffffff bold',
+        Keyword.Type:       '#cdcaa9 bold',
+        Generic.Subheading: '#ffffff bold',
+        Name.Constant:      '#0086d2',
+        Comment.Preproc:    '#ff0007 bold'
+    }