chore: remove postinstall script

Building WASM should be an explicit step, not part of dependency installation.

Changes:
- Remove postinstall script from package.json
- Update README.md to remove postinstall mention
- Update INSTALL.md to clarify git installs need manual build

Benefits:
- fmt/lint/typecheck CI jobs no longer need Zig or submodules
- Cleaner separation: install = deps, build = artifacts
- Users have explicit control over when WASM is built

Author: sreya

INSTALL.md

@@ -20,7 +20,7 @@ npm install github:coder/ghostty-web
 bun add github:coder/ghostty-web
 ```
 
-**Note:** When installing from git, the package automatically builds itself via a `postinstall` script. This requires Bun to be installed and may take a few seconds during installation.
+**Note:** Git installs require manually building the package first. See [Local Development](#local-development) for build instructions.
 
 ## Basic Usage
 
@@ -91,7 +91,7 @@ ws.onmessage = (event) => {
 
 ## WASM File Handling
 
-The library requires the `ghostty-vt.wasm` file at runtime. When installing from npm, the WASM is pre-built and included. When installing from git, it's built during `postinstall`.
+The library requires the `ghostty-vt.wasm` file at runtime. When installing from npm, the WASM is pre-built and included in the package.
 
 ### Local Development
 

README.md

@@ -14,8 +14,6 @@ Or install from GitHub:
 npm install github:coder/ghostty-web
 ```
 
-**Note:** Git installs will auto-build during `postinstall` (requires Bun).
-
 ## Quick Start
 
 ```typescript

package.json

@@ -58,8 +58,7 @@
     "fmt:fix": "prettier --write .",
     "lint": "biome check .",
     "lint:fix": "biome check --write .",
-    "prepublishOnly": "bun run test && bun run build",
-    "postinstall": "[ -d dist ] || bun run build"
+    "prepublishOnly": "bun run test && bun run build"
   },
   "devDependencies": {
     "@biomejs/biome": "^1.9.4",