feat: Add GDScript (.gd) language support for Godot projects

**Problem:**
Godot projects with 267 GDScript files were only analyzing 13 C# files,
missing 95%+ of the codebase.

**Changes:**
1. Added `.gd` → "GDScript" to LANGUAGE_EXTENSIONS mapping
2. Added GDScript support to code_analyzer.py (uses Python AST parser)
3. Added GDScript support to dependency_analyzer.py (uses Python import extraction)

**Known Limitation:**
GDScript has syntax differences from Python (extends, @export, signals, etc.)
so Python AST parser may fail on some files. Future enhancement needed:
- Create GDScript-specific regex-based parser
- Handle Godot-specific keywords (extends, signal, @export, preload, etc.)

**Test Results:**
Before: 13 files analyzed (C# only)
After:  280 files detected (13 C# + 267 GDScript)
Status: GDScript files detected but analysis may fail due to syntax differences

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

src/skill_seekers/cli/codebase_scraper.py

@@ -68,6 +68,7 @@ LANGUAGE_EXTENSIONS = {
     ".hxx": "C++",
     ".c": "C",
     ".cs": "C#",
+    ".gd": "GDScript",  # Godot scripting language
     ".go": "Go",
     ".rs": "Rust",
     ".java": "Java",