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/cli.ts

@@ -0,0 +1,66 @@
+import { spawn } from "bun"
+import { SG_CLI_PATH } from "./constants"
+import type { CliMatch, CliLanguage } from "./types"
+
+export interface RunOptions {
+  pattern: string
+  lang: CliLanguage
+  paths?: string[]
+  globs?: string[]
+  rewrite?: string
+  context?: number
+  updateAll?: boolean
+}
+
+export async function runSg(options: RunOptions): Promise<CliMatch[]> {
+  const args = ["run", "-p", options.pattern, "--lang", options.lang, "--json=compact"]
+
+  if (options.rewrite) {
+    args.push("-r", options.rewrite)
+    if (options.updateAll) {
+      args.push("--update-all")
+    }
+  }
+
+  if (options.context && options.context > 0) {
+    args.push("-C", String(options.context))
+  }
+
+  if (options.globs) {
+    for (const glob of options.globs) {
+      args.push("--globs", glob)
+    }
+  }
+
+  const paths = options.paths && options.paths.length > 0 ? options.paths : ["."]
+  args.push(...paths)
+
+  const proc = spawn([SG_CLI_PATH, ...args], {
+    stdout: "pipe",
+    stderr: "pipe",
+  })
+
+  const stdout = await new Response(proc.stdout).text()
+  const stderr = await new Response(proc.stderr).text()
+  const exitCode = await proc.exited
+
+  if (exitCode !== 0 && stdout.trim() === "") {
+    if (stderr.includes("No files found")) {
+      return []
+    }
+    if (stderr.trim()) {
+      throw new Error(stderr.trim())
+    }
+    return []
+  }
+
+  if (!stdout.trim()) {
+    return []
+  }
+
+  try {
+    return JSON.parse(stdout) as CliMatch[]
+  } catch {
+    return []
+  }
+}