perf(coding-agent): optimized documentation indexing via compressed blob

- Replaced raw TypeScript documentation map with a lazily-inflated gzip blob.
- Reduced bundled binary/npm package size by approximately 0.9MB.
- Encapsulated index logic into `docs-index.ts` to separate header metadata from content.
- Added `postpack` and robust `try/finally` patterns in build scripts to ensure clean artifacts.
- Implemented disk-based fallback during development to maintain existing developer experience.

packages/coding-agent/scripts/build-binary.ts

@@ -38,8 +38,11 @@ async function runCommand(
 }
 
 async function main(): Promise<void> {
-	await runCommand(["bun", "--cwd=../stats", "scripts/generate-client-bundle.ts", "--generate"]);
+	// Generate inside the try so the finally always restores the empty checked-in
+	// placeholders (stats client archive, docs index) even on failure.
 	try {
+		await runCommand(["bun", "--cwd=../stats", "scripts/generate-client-bundle.ts", "--generate"]);
+		await runCommand(["bun", "scripts/generate-docs-index.ts", "--generate"]);
 		await runCommand(["bun", "--cwd=../natives", "run", "embed:native"]);
 		try {
 			const buildEnv = shouldAdhocSignDarwinBinary() ? { ...Bun.env, BUN_NO_CODESIGN_MACHO_BINARY: "1" } : Bun.env;
@@ -98,6 +101,7 @@ async function main(): Promise<void> {
 		}
 	} finally {
 		await runCommand(["bun", "--cwd=../stats", "scripts/generate-client-bundle.ts", "--reset"]);
+		await runCommand(["bun", "scripts/generate-docs-index.ts", "--reset"]);
 	}
 }