refactor: migrate from tsx to bun as TypeScript runtime

Remove tsx dependency and update all dev scripts and documentation to use bun
as the primary TypeScript runtime for development. Consolidate process detection
logic in daemon.ts to check for dev mode via src/index.ts regardless of runtime.

cli/src/daemon/README.md

@@ -264,7 +264,7 @@ All data is plain JSON over TLS; authentication is `CLI_API_TOKEN` (no end-to-en
 
 `hapi doctor` uses `ps aux | grep` to find all HAPI processes:
 - Production: matches `hapi` binary, `happy-coder`
-- Development: matches `tsx.*src/index.ts`
+- Development: matches `src/index.ts` (run via `bun`)
 - Categorizes by command args: daemon, daemon-spawned, user-session, doctor
 
 ### Clean Runaway Processes

cli/src/daemon/daemon.integration.test.ts

@@ -256,7 +256,7 @@ describe.skipIf(!await isServerHealthy())('Daemon Integration Tests', { timeout:
   it('should not allow starting a second daemon', async () => {
     // Daemon is already running from beforeEach
     // Try to start another daemon
-    const secondChild = spawn('yarn', ['tsx', 'src/index.ts', 'daemon', 'start-sync'], {
+    const secondChild = spawn('bun', ['src/index.ts', 'daemon', 'start-sync'], {
       cwd: process.cwd(),
       env: process.env,
       stdio: ['ignore', 'pipe', 'pipe']

cli/src/daemon/doctor.ts

@@ -22,12 +22,13 @@ export async function findAllHappyProcesses(): Promise<Array<{ pid: number, comm
       
       // Check if it's a HAPI process
       const isHappyBinary = name === 'hapi' || name === 'hapi.exe' || /\bhapi(\.exe)?\b/.test(cmd);
+      // Dev mode: running via bun/node with src/index.ts (production uses compiled binary)
+      const isDevMode = cmd.includes('src/index.ts');
       const isHappy = name.includes('happy') ||
                       name === 'node' && cmd.includes('happy-cli') ||
                       cmd.includes('happy-coder') ||
                       isHappyBinary ||
-                      (cmd.includes('tsx') && cmd.includes('src/index.ts') && cmd.includes('happy-cli')) ||
-                      (cmd.includes('bun') && cmd.includes('src/index.ts') && cmd.includes('happy-cli'));
+                      isDevMode;
       
       if (!isHappy) continue;
 
@@ -36,17 +37,17 @@ export async function findAllHappyProcesses(): Promise<Array<{ pid: number, comm
       if (proc.pid === process.pid) {
         type = 'current';
       } else if (cmd.includes('--version')) {
-        type = cmd.includes('tsx') ? 'dev-daemon-version-check' : 'daemon-version-check';
+        type = isDevMode ? 'dev-daemon-version-check' : 'daemon-version-check';
       } else if (cmd.includes('daemon start-sync') || cmd.includes('daemon start')) {
-        type = cmd.includes('tsx') ? 'dev-daemon' : 'daemon';
+        type = isDevMode ? 'dev-daemon' : 'daemon';
       } else if (cmd.includes('--started-by daemon')) {
-        type = cmd.includes('tsx') ? 'dev-daemon-spawned' : 'daemon-spawned-session';
+        type = isDevMode ? 'dev-daemon-spawned' : 'daemon-spawned-session';
       } else if (cmd.includes('doctor')) {
-        type = cmd.includes('tsx') ? 'dev-doctor' : 'doctor';
+        type = isDevMode ? 'dev-doctor' : 'doctor';
       } else if (cmd.includes('--yolo')) {
         type = 'dev-session';
       } else {
-        type = cmd.includes('tsx') ? 'dev-related' : 'user-session';
+        type = isDevMode ? 'dev-related' : 'user-session';
       }
 
       allProcesses.push({ pid: proc.pid, command: cmd || name, type });

cli/src/utils/spawnHappyCLI.ts

@@ -5,7 +5,7 @@
  *
  * HAPI CLI runs in two modes:
  * 1. **Compiled binary**: A single executable built with `bun build --compile`
- * 2. **Development mode**: Running TypeScript directly via `tsx` or `bun`
+ * 2. **Development mode**: Running TypeScript directly via `bun`
  *
  * ## Execution Modes
  *
@@ -15,7 +15,7 @@
  * - No additional entrypoint needed - just pass args to `process.execPath`
  *
  * **Development Mode:**
- * - Running via `tsx src/index.ts` or `bun src/index.ts`
+ * - Running via `bun src/index.ts`
  * - Spawn child processes using the same runtime with `src/index.ts` entrypoint
  *
  * ## Cross-Platform Support
@@ -70,7 +70,7 @@ export function getHappyCliCommand(args: string[]): HappyCliCommand {
     };
   }
 
-  // Node.js with tsx: preserve execArgv (which includes tsx loader)
+  // Node.js fallback: preserve execArgv (for compatibility)
   return {
     command: process.execPath,
     args: [...process.execArgv, entrypoint, ...args]