fix: block extension declaration deletions

package.json

@@ -96,7 +96,8 @@
 		"typecheck": "npm run build:pi && tsc --noEmit",
 		"typecheck:extensions": "npm run check:versioned-json && tsc --noEmit --project tsconfig.extensions.json",
 		"check:sf-inventory": "node scripts/check-sf-extension-inventory.mjs",
-		"check:versioned-json": "node scripts/check-versioned-json.mjs && npm run check:sf-inventory",
+		"check:protected-deletions": "node scripts/check-protected-deletions.mjs",
+		"check:versioned-json": "node scripts/check-protected-deletions.mjs && node scripts/check-versioned-json.mjs && npm run check:sf-inventory",
 		"format": "biome format --write .",
 		"format:check": "biome format .",
 		"lint": "npm run check:versioned-json && biome check .",

scripts/check-protected-deletions.mjs

@@ -0,0 +1,40 @@
+#!/usr/bin/env node
+import { execFileSync } from "node:child_process";
+
+const PROTECTED_PATHS = [":(glob)src/resources/extensions/**/*.d.ts"];
+
+function git(args) {
+	return execFileSync("git", args, {
+		stdio: ["ignore", "pipe", "pipe"],
+		encoding: "utf-8",
+	}).trim();
+}
+
+function listDeleted(cached) {
+	const args = ["diff", "--name-only", "--diff-filter=D"];
+	if (cached) args.push("--cached");
+	args.push("--", ...PROTECTED_PATHS);
+	const out = git(args);
+	return out ? out.split("\n").filter(Boolean) : [];
+}
+
+const stagedOnly = process.argv.includes("--cached");
+const deleted = stagedOnly
+	? listDeleted(true)
+	: [...new Set([...listDeleted(false), ...listDeleted(true)])];
+
+if (deleted.length > 0) {
+	const mode = stagedOnly ? "staged " : "";
+	process.stderr.write(
+		`check-protected-deletions: refusing ${mode}protected declaration deletions:\n`,
+	);
+	for (const path of deleted) {
+		process.stderr.write(`  ${path}\n`);
+	}
+	process.stderr.write(
+		"\nRestore these files or make an explicit reviewed deletion outside automation.\n",
+	);
+	process.exit(1);
+}
+
+process.stdout.write("check-protected-deletions: ok\n");

scripts/install-hooks.mjs

@@ -11,6 +11,7 @@ import {
 import { join } from "node:path";
 
 const MARKER = "# sf-secret-scan";
+const PROTECTED_DELETIONS_MARKER = "# sf-protected-deletions";
 
 function git(args) {
 	return execFileSync("git", args, {
@@ -24,19 +25,35 @@ const repoRoot = git(["rev-parse", "--show-toplevel"]);
 const hookDir = join(gitDir, "hooks");
 const hookFile = join(hookDir, "pre-commit");
 const hookCommand = `node "${join(repoRoot, "scripts", "secret-scan.mjs")}"`;
+const protectedDeletionsCommand = `node "${join(
+	repoRoot,
+	"scripts",
+	"check-protected-deletions.mjs",
+)}" --cached`;
 
 mkdirSync(hookDir, { recursive: true });
 
 if (existsSync(hookFile)) {
 	const current = readFileSync(hookFile, "utf8");
-	if (current.includes(MARKER)) {
-		process.stdout.write("secret-scan pre-commit hook already installed.\n");
+	const additions = [];
+	if (!current.includes(MARKER)) {
+		additions.push(MARKER, hookCommand);
+	}
+	if (!current.includes(PROTECTED_DELETIONS_MARKER)) {
+		additions.push(
+			PROTECTED_DELETIONS_MARKER,
+			"# Pre-commit hook: block accidental deletion of hand-written extension declarations",
+			protectedDeletionsCommand,
+		);
+	}
+	if (additions.length === 0) {
+		process.stdout.write("sf pre-commit hooks already installed.\n");
 		process.exit(0);
 	}
 
-	const next = `${current.replace(/\s*$/, "\n")}${MARKER}\n${hookCommand}\n`;
+	const next = `${current.replace(/\s*$/, "\n")}${additions.join("\n")}\n`;
 	writeFileSync(hookFile, next, "utf8");
-	process.stdout.write("secret-scan appended to existing pre-commit hook.\n");
+	process.stdout.write("sf pre-commit hooks appended to existing hook.\n");
 	process.exit(0);
 }
 
@@ -46,6 +63,10 @@ const hookBody = [
 	"# Pre-commit hook: scan staged files for hardcoded secrets",
 	hookCommand,
 	"",
+	"# sf-protected-deletions",
+	"# Pre-commit hook: block accidental deletion of hand-written extension declarations",
+	protectedDeletionsCommand,
+	"",
 ].join("\n");
 
 writeFileSync(hookFile, hookBody, "utf8");
@@ -55,4 +76,4 @@ try {
 	// Best effort on Windows filesystems that do not honor chmod.
 }
 
-process.stdout.write("secret-scan pre-commit hook installed.\n");
+process.stdout.write("sf pre-commit hooks installed.\n");