feat(tools): add ast-grep tools for AST-aware code search and transformation

- Add ast_grep_search for pattern-based code search (25 languages)
- Add ast_grep_replace for AST-aware code rewriting with dry-run
- Add ast_grep_analyze for in-memory code analysis (NAPI)
- Add ast_grep_transform for in-memory code transformation
- Add ast_grep_languages to list supported languages

src/tools/ast-grep/constants.ts

@@ -0,0 +1,63 @@
+// ast-grep CLI path (homebrew installed)
+export const SG_CLI_PATH = "sg"
+
+// CLI supported languages (25 total)
+export const CLI_LANGUAGES = [
+  "bash",
+  "c",
+  "cpp",
+  "csharp",
+  "css",
+  "elixir",
+  "go",
+  "haskell",
+  "html",
+  "java",
+  "javascript",
+  "json",
+  "kotlin",
+  "lua",
+  "nix",
+  "php",
+  "python",
+  "ruby",
+  "rust",
+  "scala",
+  "solidity",
+  "swift",
+  "typescript",
+  "tsx",
+  "yaml",
+] as const
+
+// NAPI supported languages (5 total - native bindings)
+export const NAPI_LANGUAGES = ["html", "javascript", "tsx", "css", "typescript"] as const
+
+// Language to file extensions mapping
+export const LANG_EXTENSIONS: Record<string, string[]> = {
+  bash: [".bash", ".sh", ".zsh", ".bats"],
+  c: [".c", ".h"],
+  cpp: [".cpp", ".cc", ".cxx", ".hpp", ".hxx", ".h"],
+  csharp: [".cs"],
+  css: [".css"],
+  elixir: [".ex", ".exs"],
+  go: [".go"],
+  haskell: [".hs", ".lhs"],
+  html: [".html", ".htm"],
+  java: [".java"],
+  javascript: [".js", ".jsx", ".mjs", ".cjs"],
+  json: [".json"],
+  kotlin: [".kt", ".kts"],
+  lua: [".lua"],
+  nix: [".nix"],
+  php: [".php"],
+  python: [".py", ".pyi"],
+  ruby: [".rb", ".rake"],
+  rust: [".rs"],
+  scala: [".scala", ".sc"],
+  solidity: [".sol"],
+  swift: [".swift"],
+  typescript: [".ts", ".cts", ".mts"],
+  tsx: [".tsx"],
+  yaml: [".yml", ".yaml"],
+}