refactor(ast-grep): split cli.ts and constants.ts into focused modules

Extract AST-grep tooling into single-responsibility files:
- cli-binary-path-resolution.ts, sg-cli-path.ts
- environment-check.ts, language-support.ts
- process-output-timeout.ts, sg-compact-json-output.ts

src/tools/ast-grep/language-support.ts

@@ -0,0 +1,63 @@
+// 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
+
+export const DEFAULT_TIMEOUT_MS = 300_000
+export const DEFAULT_MAX_OUTPUT_BYTES = 1 * 1024 * 1024
+export const DEFAULT_MAX_MATCHES = 500
+
+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"],
+}