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>

src/skill_seekers/cli/presets/github_presets.py

@@ -0,0 +1,117 @@
+"""GitHub command presets.
+
+Defines preset configurations for the github command.
+
+Presets:
+    quick:          Fast scraping with minimal data
+    standard:       Balanced scraping (DEFAULT)
+    full:           Comprehensive scraping with all data
+"""
+
+from dataclasses import dataclass, field
+from typing import Dict
+import argparse
+
+
+@dataclass(frozen=True)
+class GitHubPreset:
+    """Definition of a GitHub preset.
+    
+    Attributes:
+        name: Human-readable preset name
+        description: Brief description of what this preset does
+        max_issues: Maximum issues to fetch
+        features: Dict of feature flags (feature_name -> enabled)
+        estimated_time: Human-readable time estimate
+    """
+    name: str
+    description: str
+    max_issues: int
+    features: Dict[str, bool] = field(default_factory=dict)
+    estimated_time: str = ""
+
+
+# Preset definitions
+GITHUB_PRESETS = {
+    "quick": GitHubPreset(
+        name="Quick",
+        description="Fast scraping with minimal data (README + code)",
+        max_issues=10,
+        features={
+            "include_issues": False,
+            "include_changelog": True,
+            "include_releases": False,
+        },
+        estimated_time="1-3 minutes"
+    ),
+    
+    "standard": GitHubPreset(
+        name="Standard",
+        description="Balanced scraping with issues and releases (recommended)",
+        max_issues=100,
+        features={
+            "include_issues": True,
+            "include_changelog": True,
+            "include_releases": True,
+        },
+        estimated_time="5-15 minutes"
+    ),
+    
+    "full": GitHubPreset(
+        name="Full",
+        description="Comprehensive scraping with all available data",
+        max_issues=500,
+        features={
+            "include_issues": True,
+            "include_changelog": True,
+            "include_releases": True,
+        },
+        estimated_time="20-60 minutes"
+    ),
+}
+
+
+def apply_github_preset(args: argparse.Namespace, preset_name: str) -> None:
+    """Apply a GitHub preset to the args namespace.
+    
+    Args:
+        args: The argparse.Namespace to modify
+        preset_name: Name of the preset to apply
+        
+    Raises:
+        KeyError: If preset_name is not a valid preset
+    """
+    preset = GITHUB_PRESETS[preset_name]
+    
+    # Apply max_issues only if not set by user
+    if args.max_issues is None or args.max_issues == 100:  # 100 is default
+        args.max_issues = preset.max_issues
+    
+    # Apply feature flags (only if not explicitly disabled by user)
+    for feature, enabled in preset.features.items():
+        skip_attr = f"no_{feature}"
+        if not hasattr(args, skip_attr) or not getattr(args, skip_attr):
+            setattr(args, skip_attr, not enabled)
+
+
+def show_github_preset_list() -> None:
+    """Print the list of available GitHub presets to stdout."""
+    print("\nAvailable GitHub Presets")
+    print("=" * 60)
+    print()
+    
+    for name, preset in GITHUB_PRESETS.items():
+        marker = " (DEFAULT)" if name == "standard" else ""
+        print(f"  {name}{marker}")
+        print(f"    {preset.description}")
+        print(f"    Estimated time: {preset.estimated_time}")
+        print(f"    Max issues: {preset.max_issues}")
+        
+        # Show enabled features
+        enabled = [f.replace("include_", "") for f, v in preset.features.items() if v]
+        if enabled:
+            print(f"    Features: {', '.join(enabled)}")
+        print()
+    
+    print("Usage: skill-seekers github --repo <owner/repo> --preset <name>")
+    print()