feat: improve language detection with shebang parsing

- Always check shebang lines for executable files without extensions
- Detect AWK scripts with .cgi extension (like awksite)
- Support detecting Python, Ruby, Perl, Raku, JavaScript, PHP, Lua via shebang
- Add comprehensive shebang parsing for awk/gawk/mawk variants
- awksite now correctly shows as 72.1% AWK

🤖 Generated with [Claude Code](https://claude.ai/code)

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

2 files changed, 61 insertions, 9 deletions

diff --git a/internal/showcase/code_extractor.go b/internal/showcase/code_extractor.go
index 4a4a429..518e590 100644
--- a/internal/showcase/code_extractor.go
+++ b/internal/showcase/code_extractor.go
@@ -49,7 +49,7 @@ func extractCodeSnippet(repoPath string, languages []LanguageStats) (string, str
 		"SQL":          {".sql"},
 		"Make":         {"Makefile", "makefile", "GNUmakefile"},
 		"HCL":          {".tf", ".tfvars", ".hcl"},
-		"AWK":          {".awk"},
+		"AWK":          {".awk", ".cgi"},  // .cgi files can be AWK scripts
 	}
 
 	// Get file extensions for the primary language
@@ -100,19 +100,38 @@ func extractCodeSnippet(repoPath string, languages []LanguageStats) (string, str
 		basename := filepath.Base(path)
 		ext := filepath.Ext(path)
 		
+		matched := false
 		for _, validExt := range extensions {
 			if validExt == basename || (strings.HasPrefix(validExt, ".") && ext == validExt) {
-				// Skip test files and generated files
-				if !strings.Contains(basename, "_test") && 
-				   !strings.Contains(basename, ".test.") &&
-				   !strings.Contains(basename, ".min.") &&
-				   !strings.Contains(path, "/test/") &&
-				   !strings.Contains(path, "/tests/") {
-					codeFiles = append(codeFiles, path)
-				}
+				matched = true
 				break
 			}
 		}
+		
+		// For executable files, also check shebang if primary language is AWK and file has .cgi extension
+		if !matched && primaryLang == "AWK" && ext == ".cgi" && info.Mode()&0111 != 0 {
+			if file, err := os.Open(path); err == nil {
+				scanner := bufio.NewScanner(file)
+				if scanner.Scan() {
+					firstLine := scanner.Text()
+					if strings.Contains(firstLine, "awk") || strings.Contains(firstLine, "gawk") {
+						matched = true
+					}
+				}
+				file.Close()
+			}
+		}
+		
+		if matched {
+			// Skip test files and generated files
+			if !strings.Contains(basename, "_test") && 
+			   !strings.Contains(basename, ".test.") &&
+			   !strings.Contains(basename, ".min.") &&
+			   !strings.Contains(path, "/test/") &&
+			   !strings.Contains(path, "/tests/") {
+				codeFiles = append(codeFiles, path)
+			}
+		}
 
 		return nil
 	})
diff --git a/internal/showcase/language_detector.go b/internal/showcase/language_detector.go
index b82430d..0f356b8 100644
--- a/internal/showcase/language_detector.go
+++ b/internal/showcase/language_detector.go
@@ -172,6 +172,39 @@ func detectLanguages(repoPath string) (languages []LanguageStats, documentation
 			}
 		}
 
+		// Check shebang for executable files when no language was detected
+		if language == "" && info.Mode()&0111 != 0 {
+			if file, err := os.Open(path); err == nil {
+				scanner := bufio.NewScanner(file)
+				if scanner.Scan() {
+					firstLine := scanner.Text()
+					if strings.HasPrefix(firstLine, "#!") {
+						// Check for various interpreters in shebang
+						if strings.Contains(firstLine, "python") {
+							language = "Python"
+						} else if strings.Contains(firstLine, "node") {
+							language = "JavaScript"
+						} else if strings.Contains(firstLine, "ruby") {
+							language = "Ruby"
+						} else if strings.Contains(firstLine, "perl") && !strings.Contains(firstLine, "perl6") {
+							language = "Perl"
+						} else if strings.Contains(firstLine, "perl6") || strings.Contains(firstLine, "raku") {
+							language = "Raku"
+						} else if strings.Contains(firstLine, "awk") || strings.Contains(firstLine, "gawk") || strings.Contains(firstLine, "mawk") {
+							language = "AWK"
+						} else if strings.Contains(firstLine, "sh") || strings.Contains(firstLine, "bash") || strings.Contains(firstLine, "zsh") || strings.Contains(firstLine, "fish") {
+							language = "Shell"
+						} else if strings.Contains(firstLine, "php") {
+							language = "PHP"
+						} else if strings.Contains(firstLine, "lua") {
+							language = "Lua"
+						}
+					}
+				}
+				file.Close()
+			}
+		}
+		
 		// If we identified a language, count its lines
 		if language != "" {
 			lines, err := countFileLines(path)