fix: Resolve all linting errors from ruff

Fix 145 linting errors across CLI refactor code:

Type annotation modernization (Python 3.9+):
- Replace typing.Dict with dict
- Replace typing.List with list
- Replace typing.Set with set
- Replace Optional[X] with X | None

Code quality improvements:
- Remove trailing whitespace (W291)
- Remove whitespace from blank lines (W293)
- Remove unused imports (F401)
- Use dictionary lookup instead of if-elif chains (SIM116)
- Combine nested if statements (SIM102)

Files fixed (45 files):
- src/skill_seekers/cli/arguments/*.py (10 files)
- src/skill_seekers/cli/parsers/*.py (24 files)
- src/skill_seekers/cli/presets/*.py (4 files)
- src/skill_seekers/cli/create_command.py
- src/skill_seekers/cli/source_detector.py
- src/skill_seekers/cli/github_scraper.py
- tests/test_*.py (5 test files)

All files now pass ruff linting checks.

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

src/skill_seekers/cli/presets/github_presets.py

@@ -9,14 +9,13 @@ Presets:
 """
 
 from dataclasses import dataclass, field
-from typing import Dict
-import argparse
 
+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
@@ -27,10 +26,9 @@ class GitHubPreset:
     name: str
     description: str
     max_issues: int
-    features: Dict[str, bool] = field(default_factory=dict)
+    features: dict[str, bool] = field(default_factory=dict)
     estimated_time: str = ""
 
-
 # Preset definitions
 GITHUB_PRESETS = {
     "quick": GitHubPreset(
@@ -44,7 +42,7 @@ GITHUB_PRESETS = {
         },
         estimated_time="1-3 minutes"
     ),
-    
+
     "standard": GitHubPreset(
         name="Standard",
         description="Balanced scraping with issues and releases (recommended)",
@@ -56,7 +54,7 @@ GITHUB_PRESETS = {
         },
         estimated_time="5-15 minutes"
     ),
-    
+
     "comprehensive": GitHubPreset(
         name="Comprehensive",
         description="Comprehensive scraping with all available data",
@@ -70,48 +68,46 @@ GITHUB_PRESETS = {
     ),
 }
 
-
 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()