feat(cli): add Bun single executable binary support

Enables building hapi as standalone Bun-compiled executables for macOS,
Linux, and Windows (x64/arm64). Adds build script, bootstrap entry point,
runtime asset management, and automatic deployment of bundled tools
(ripgrep, difftastic). Includes MCP stdio bridge support and proper
environment handling for compiled binaries. Updates documentation with
build and installation instructions for single executable distribution.

cli/src/daemon/doctor.ts

@@ -21,10 +21,12 @@ export async function findAllHappyProcesses(): Promise<Array<{ pid: number, comm
       const name = proc.name || '';
       
       // Check if it's a Happy process
+      const isHappyBinary = name === 'hapi' || name === 'hapi.exe' || /\bhapi(\.exe)?\b/.test(cmd);
       const isHappy = name.includes('happy') || 
                       name === 'node' && (cmd.includes('happy-cli') || cmd.includes('dist/index.mjs')) ||
                       cmd.includes('happy.mjs') ||
                       cmd.includes('happy-coder') ||
+                      isHappyBinary ||
                       (cmd.includes('tsx') && cmd.includes('src/index.ts') && cmd.includes('happy-cli'));
       
       if (!isHappy) continue;
@@ -120,4 +122,4 @@ export async function killRunawayHappyProcesses(): Promise<{ killed: number, err
   }
 
   return { killed, errors };
-}
+}

cli/src/daemon/run.ts

@@ -1,6 +1,5 @@
 import fs from 'fs/promises';
 import os from 'os';
-import * as tmp from 'tmp';
 
 import { ApiClient } from '@/api/api';
 import { TrackedSession } from './types';
@@ -233,14 +232,14 @@ export async function startDaemon(): Promise<void> {
           if (options.agent === 'codex') {
 
             // Create a temporary directory for Codex
-            const codexHomeDir = tmp.dirSync();
+            const codexHomeDir = await fs.mkdtemp(join(os.tmpdir(), 'hapi-codex-'));
 
             // Write the token to the temporary directory
-            fs.writeFile(join(codexHomeDir.name, 'auth.json'), options.token);
+            await fs.writeFile(join(codexHomeDir, 'auth.json'), options.token);
 
             // Set the environment variable for Codex
             extraEnv = {
-              CODEX_HOME: codexHomeDir.name
+              CODEX_HOME: codexHomeDir
             };
           } else { // Assuming claude
             extraEnv = {