fix: security and stability fixes from code review

- Scope WebSocket auth bypass to only WS endpoints by restructuring
  routes into separate chi Groups. Non-WS routes no longer passthrough
  unauthenticated requests with spoofed Upgrade headers. Added
  optionalAPIKeyOrJWT middleware for WS routes (injects auth context
  from API key/JWT if present, passes through otherwise) and
  markAdminWS middleware for admin WS routes.

- Fix nil pointer dereference in envd Handler.Wait() — p.tty.Close()
  was called unconditionally but p.tty is nil for non-PTY processes,
  crashing every non-PTY process exit.

- Fix goroutine leak in sandbox Pause — stopSampler was never called,
  leaking one sampler goroutine per successful pause operation.

- Decouple PTY WebSocket reads from RPC dispatch using a buffered
  channel to prevent backpressure-induced connection drops under fast
  typing. Includes input coalescing to reduce RPC call volume.

VERSION_CP

@@ -1 +1 @@
-0.1.3
+0.1.4