fix: Framework detection now works by including import-only files (fixes #239)

## Problem
Framework detection was broken because files with only imports (no
classes/functions) were excluded from analysis. The architectural pattern
detector received empty file lists, resulting in 0 frameworks detected.

## Root Cause
In codebase_scraper.py:873-881, the has_content check filtered out files
that didn't have classes, functions, or other structural elements. This
excluded simple __init__.py files that only contained import statements,
which are critical for framework detection.

## Solution (3 parts)

1. **Extract imports from Python files** (code_analyzer.py:140-178)
   - Added import extraction using AST (ast.Import, ast.ImportFrom)
   - Returns imports list in analysis results
   - Now captures: "from flask import Flask" → ["flask"]

2. **Include import-only files** (codebase_scraper.py:873-881)
   - Updated has_content check to include files with imports
   - Files with imports are now included in analysis results
   - Comment added: "IMPORTANT: Include files with imports for framework
     detection (fixes #239)"

3. **Enhance framework detection** (architectural_pattern_detector.py:195-240)
   - Extract imports from all Python files in analysis
   - Check imports in addition to file paths and directory structure
   - Prioritize import-based detection (high confidence)
   - Require 2+ matches for path-based detection (avoid false positives)
   - Added debug logging: "Collected N imports for framework detection"

## Results

**Before fix:**
- Test Flask project: 0 files analyzed, 0 frameworks detected
- Files with imports: excluded from analysis
- Framework detection: completely broken

**After fix:**
- Test Flask project: 3 files analyzed, Flask detected ✅
- Files with imports: included in analysis
- Framework detection: working correctly
- No false positives (ASP.NET, Rails, etc.)

## Testing

Added comprehensive test suite (tests/test_framework_detection.py):
- ✅ test_flask_framework_detection_from_imports
- ✅ test_files_with_imports_are_included
- ✅ test_no_false_positive_frameworks

All existing tests pass:
- ✅ 38 tests in test_codebase_scraper.py
- ✅ 54 tests in test_code_analyzer.py
- ✅ 3 new tests in test_framework_detection.py

## Impact

- Fixes issue #239 completely
- Framework detection now works for Python projects
- Import-only files (common in Python packages) are properly analyzed
- No performance impact (import extraction is fast)
- No breaking changes to existing functionality

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

src/skill_seekers/cli/architectural_pattern_detector.py

@@ -200,6 +200,16 @@ class ArchitecturalPatternDetector:
         all_paths = [str(f.get("file", "")) for f in files]
         all_content = " ".join(all_paths)
 
+        # Extract all imports from Python files (fixes #239)
+        all_imports = []
+        for file_data in files:
+            if file_data.get("language") == "Python" and file_data.get("imports"):
+                all_imports.extend(file_data["imports"])
+
+        # Create searchable import string
+        import_content = " ".join(all_imports)
+        logger.debug(f"Collected {len(all_imports)} imports for framework detection")
+
         # Also check actual directory structure for game engine markers
         # (project.godot, .unity, .uproject are config files, not in analyzed files)
         dir_files = []
@@ -227,15 +237,27 @@ class ArchitecturalPatternDetector:
                     # Return early to prevent web framework false positives
                     return detected
 
-        # Check other frameworks
+        # Check other frameworks (including imports - fixes #239)
         for framework, markers in self.FRAMEWORK_MARKERS.items():
             if framework in ["Unity", "Unreal", "Godot"]:
                 continue  # Already checked
 
-            matches = sum(1 for marker in markers if marker.lower() in all_content.lower())
-            if matches >= 2:
+            # Check in file paths, directory structure, AND imports
+            path_matches = sum(1 for marker in markers if marker.lower() in all_content.lower())
+            dir_matches = sum(1 for marker in markers if marker.lower() in dir_content.lower())
+            import_matches = sum(1 for marker in markers if marker.lower() in import_content.lower())
+
+            # Strategy: Prioritize import-based detection (more accurate)
+            # If we have import matches, they're strong signals - use them alone
+            # Otherwise, require 2+ matches from paths/dirs
+            if import_matches >= 1:
+                # Import-based detection (high confidence)
                 detected.append(framework)
-                logger.info(f"  📦 Detected framework: {framework}")
+                logger.info(f"  📦 Detected framework: {framework} (imports:{import_matches})")
+            elif (path_matches + dir_matches) >= 2:
+                # Path/directory-based detection (requires 2+ matches)
+                detected.append(framework)
+                logger.info(f"  📦 Detected framework: {framework} (path:{path_matches} dir:{dir_matches})")
 
         return detected