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/gruvbox.py

@@ -0,0 +1,118 @@
+"""
+    pygments.styles.gruvbox
+    ~~~~~~~~~~~~~~~~~~~~~~~
+
+    pygments version of the "gruvbox" vim theme.
+    https://github.com/morhetz/gruvbox
+
+    :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, Keyword, Name, Comment, String, Error, \
+     Number, Operator, Generic
+
+
+__all__ = ['GruvboxDarkStyle', 'GruvboxLightStyle']
+
+
+class GruvboxDarkStyle(Style):
+    """
+    Pygments version of the "gruvbox" dark vim theme.
+    """
+    
+    name = 'gruvbox-dark'
+
+    background_color = '#282828'
+    highlight_color = '#ebdbb2'
+
+    styles = {
+        Token:              '#dddddd',
+
+        Comment:            'italic #928374',
+        Comment.PreProc:    '#8ec07c',
+        Comment.Special:    'bold italic #ebdbb2',
+
+        Keyword:            '#fb4934',
+        Operator.Word:      '#fb4934',
+
+        String:             '#b8bb26',
+        String.Escape:      '#fe8019',
+
+        Number:             '#d3869b',
+
+        Name.Builtin:       '#fe8019',
+        Name.Variable:      '#83a598',
+        Name.Constant:      '#d3869b',
+        Name.Class:         '#8ec07c',
+        Name.Function:      '#8ec07c',
+        Name.Namespace:     '#8ec07c',
+        Name.Exception:     '#fb4934',
+        Name.Tag:           '#8ec07c',
+        Name.Attribute:     '#fabd2f',
+        Name.Decorator:     '#fb4934',
+
+        Generic.Heading:    'bold #ebdbb2',
+        Generic.Subheading: 'underline #ebdbb2',
+        Generic.Deleted:    'bg:#fb4934 #282828',
+        Generic.Inserted:   'bg:#b8bb26 #282828',
+        Generic.Error:      '#fb4934',
+        Generic.Emph:       'italic',
+        Generic.Strong:     'bold',
+        Generic.EmphStrong: 'bold italic',
+        Generic.Prompt:     '#a89984',
+        Generic.Output:     '#f2e5bc',
+        Generic.Traceback:  '#fb4934',
+
+        Error:              'bg:#fb4934 #282828'
+    }
+
+
+class GruvboxLightStyle(Style):
+    """
+    Pygments version of the "gruvbox" Light vim theme.
+    """
+
+    name = 'gruvbox-light'
+
+    background_color = '#fbf1c7'
+    highlight_color = '#3c3836'
+
+    styles = {
+        Comment:            'italic #928374',
+        Comment.PreProc:    '#427b58',
+        Comment.Special:    'bold italic #3c3836',
+
+        Keyword:            '#9d0006',
+        Operator.Word:      '#9d0006',
+
+        String:             '#79740e',
+        String.Escape:      '#af3a03',
+
+        Number:             '#8f3f71',
+
+        Name.Builtin:       '#af3a03',
+        Name.Variable:      '#076678',
+        Name.Constant:      '#8f3f71',
+        Name.Class:         '#427b58',
+        Name.Function:      '#427b58',
+        Name.Namespace:     '#427b58',
+        Name.Exception:     '#9d0006',
+        Name.Tag:           '#427b58',
+        Name.Attribute:     '#b57614',
+        Name.Decorator:     '#9d0006',
+
+        Generic.Heading:    'bold #3c3836',
+        Generic.Subheading: 'underline #3c3836',
+        Generic.Deleted:    'bg:#9d0006 #fbf1c7',
+        Generic.Inserted:   'bg:#79740e #fbf1c7',
+        Generic.Error:      '#9d0006',
+        Generic.Emph:       'italic',
+        Generic.Strong:     'bold',
+        Generic.Prompt:     '#7c6f64',
+        Generic.Output:     '#32302f',
+        Generic.Traceback:  '#9d0006',
+
+        Error:              'bg:#9d0006 #fbf1c7'
+    }