fix: bundle server into browse binary, eliminate fallback chain

[sternryan]

Summary

• The compiled browse binary now bundles server.ts via bun build --compile, eliminating the fragile resolveServerScript() fallback chain that caused bugs in v0.3.2
• When invoked with --server, the binary runs as the persistent Chromium daemon instead of the CLI -- the CLI spawns itself with --server rather than searching for server.ts on disk
• Dev mode (bun run browse/src/cli.ts) is unchanged and still uses resolveServerScript() via lazy resolution

Technical approach

The problem: resolveServerScript() tries multiple filesystem paths to find server.ts at runtime (adjacent to cli.ts, relative to execPath, BROWSE_SERVER_SCRIPT env). In compiled binaries where import.meta.dir is inside $bunfs, this chain falls through to the execPath-relative check, which fails when the binary isn't installed in the expected browse/dist/browse directory structure.

The fix:

1. Server mode gate (top of cli.ts): Check process.argv for --server. When present, import('./server') triggers server.ts's top-level start() call. The CLI's main() is gated on !IS_SERVER_MODE.

2. Compiled binary detection: IS_COMPILED = import.meta.dir.includes('$bunfs') -- Bun's compiled binaries use a virtual filesystem prefix.

3. startServer() priority chain:

   • Windows: Node.js launcher (unchanged)
   • Compiled binary: Bun.spawn([process.execPath, '--server'], ...)
   • Dev mode: Bun.spawn(['bun', 'run', getServerScript()], ...)

4. Build change: Added --external electron to the browse binary build command. Since server.ts is now bundled, Bun follows the import chain through playwright-core which has an unused Electron loader dependency.

5. Lazy server script resolution: resolveServerScript() is now only called when actually needed (dev mode), not eagerly at module load time.

Test plan

• bun run build compiles successfully (377 modules bundled into browse binary)
• bun test test/skill-validation.test.ts test/gen-skill-docs.test.ts -- 601 tests pass
• bun test browse/test/config.test.ts -- 31 tests pass (includes resolveServerScript unit tests)
• Manual: verify browse/dist/browse status auto-starts server via --server flag
• Manual: verify bun run dev status still works via dev mode path
• Manual: verify BROWSE_SERVER_SCRIPT=/path/to/server.ts browse status still works