feat: Unified create command + consolidated enhancement flags

This commit includes two major improvements:

## 1. Unified Create Command (v3.0.0 feature)
- Auto-detects source type (web, GitHub, local, PDF, config)
- Three-tier argument organization (universal, source-specific, advanced)
- Routes to existing scrapers (100% backward compatible)
- Progressive disclosure: 15 universal flags in default help

**New files:**
- src/skill_seekers/cli/source_detector.py - Auto-detection logic
- src/skill_seekers/cli/arguments/create.py - Argument definitions
- src/skill_seekers/cli/create_command.py - Main orchestrator
- src/skill_seekers/cli/parsers/create_parser.py - Parser integration

**Tests:**
- tests/test_source_detector.py (35 tests)
- tests/test_create_arguments.py (30 tests)
- tests/test_create_integration_basic.py (10 tests)

## 2. Enhanced Flag Consolidation (Phase 1)
- Consolidated 3 flags (--enhance, --enhance-local, --enhance-level) → 1 flag
- --enhance-level 0-3 with auto-detection of API vs LOCAL mode
- Default: --enhance-level 2 (balanced enhancement)

**Modified files:**
- arguments/{common,create,scrape,github,analyze}.py - Added enhance_level
- {doc_scraper,github_scraper,config_extractor,main}.py - Updated logic
- create_command.py - Uses consolidated flag

**Auto-detection:**
- If ANTHROPIC_API_KEY set → API mode
- Else → LOCAL mode (Claude Code)

## 3. PresetManager Bug Fix
- Fixed module naming conflict (presets.py vs presets/ directory)
- Moved presets.py → presets/manager.py
- Updated __init__.py exports

**Test Results:**
- All 160+ tests passing
- Zero regressions
- 100% backward compatible

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

tests/test_analyze_command.py

@@ -48,10 +48,10 @@ class TestAnalyzeSubcommand(unittest.TestCase):
         self.assertTrue(args.comprehensive)
         # Note: Runtime will catch this and return error code 1
 
-    def test_enhance_flag(self):
-        """Test --enhance flag parsing."""
-        args = self.parser.parse_args(["analyze", "--directory", ".", "--enhance"])
-        self.assertTrue(args.enhance)
+    def test_enhance_level_flag(self):
+        """Test --enhance-level flag parsing."""
+        args = self.parser.parse_args(["analyze", "--directory", ".", "--enhance-level", "2"])
+        self.assertEqual(args.enhance_level, 2)
 
     def test_skip_flags_passed_through(self):
         """Test that skip flags are recognized."""
@@ -173,10 +173,10 @@ class TestAnalyzePresetBehavior(unittest.TestCase):
         self.assertTrue(args.comprehensive)
         # Note: Depth transformation happens in dispatch handler
 
-    def test_enhance_flag_standalone(self):
-        """Test --enhance flag can be used without presets."""
-        args = self.parser.parse_args(["analyze", "--directory", ".", "--enhance"])
-        self.assertTrue(args.enhance)
+    def test_enhance_level_standalone(self):
+        """Test --enhance-level can be used without presets."""
+        args = self.parser.parse_args(["analyze", "--directory", ".", "--enhance-level", "3"])
+        self.assertEqual(args.enhance_level, 3)
         self.assertFalse(args.quick)
         self.assertFalse(args.comprehensive)