fix: resolve CI lint and build failures

- Fixed lint path in CI workflow from src/gdiffer/ to gitignore_generator/
- Fixed verification command from gdiffer --version to gitignore --version
- Removed unused imports (pathlib.Path, typing.List, os, sys, pytest, unittest.mock.patch)
- Removed unused variable assignments (category, index)
- Fixed f-strings without placeholders
- Renamed ambiguous variable 'l' to 'line' and 'prev_line'
- Added type assertion for type narrowing in template_loader.py

gitignore_generator/cli/commands.py

@@ -2,8 +2,7 @@
 
 import os
 import sys
-from pathlib import Path
-from typing import List, Optional
+from typing import Optional
 
 import click
 
@@ -67,11 +66,9 @@ def generate(
         if template_ref.startswith("ide:"):
             template_name = template_ref[4:]
             content = template_loader.get_template_content(template_name)
-            category = "ides"
         else:
             template_name = template_ref
             content = template_loader.get_template_content(template_name)
-            category = None
 
         if content:
             content_parts.append(f"# --- {template_name} ---\n")
@@ -94,14 +91,14 @@ def generate(
     if validate:
         summary = validator.get_summary(final_content)
         if summary["errors"] > 0:
-            click.echo(f"\nValidation errors found:")
+            click.echo("\nValidation errors found:")
             for issue in summary["issues"]:
                 if issue.severity == "error":
                     click.echo(f"  Line {issue.line_number}: {issue.message}")
             if not click.confirm("Generate anyway?"):
                 sys.exit(1)
         if summary["warnings"] > 0:
-            click.echo(f"\nValidation warnings:")
+            click.echo("\nValidation warnings:")
             for issue in summary["issues"]:
                 if issue.severity == "warning":
                     click.echo(f"  Line {issue.line_number}: {issue.message}")
@@ -250,7 +247,7 @@ def template_info(template: str) -> None:
         click.echo(f"Error: Template '{template}' not found.")
         sys.exit(1)
 
-    lines = [l for l in content.splitlines() if l.strip() and not l.strip().startswith("#")]
+    lines = [line for line in content.splitlines() if line.strip() and not line.strip().startswith("#")]
 
     click.echo(f"Template: {template}")
     click.echo(f"Lines: {len(content.splitlines())}")