fix(orchestrator): envd error responses truncated to 100 chars, hiding root cause in logs and error chain

[AdaAibaby]

Problem

In packages/orchestrator/pkg/sandbox/envd.go, all envd error-response bodies are truncated to 100 characters via utils.Truncate(string(body), 100) before being embedded in fmt.Errorf strings and log fields:

```go
// line 182 — callEnvdCollapse
fmt.Errorf("collapse returned %d: %s", resp.StatusCode, utils.Truncate(string(body), 100))

// line 208 — postEnvd (covers /init, /pause, /resume, …)
fmt.Errorf("%s returned %d: %s", path, resp.StatusCode, utils.Truncate(string(body), 100))

// line 287 — CallEnvdUpgrade
fmt.Errorf("upgrade returned %d: %s", resp.StatusCode, utils.Truncate(string(body), 100))

// line 496 — initEnvd log field
zap.String("response_body", utils.Truncate(string(body), 100))
```

Because lines 182, 208, and 287 inject the truncated string directly into the error value, the truncation propagates all the way up the error chain and surfaces to callers as:

```
failed to create sandbox: failed to wait for sandbox start: failed to init new envd: /init returned 400: failed to mount "7e22c38a-5584-4730-8c31-449f5058ea19": failed to chroot into "/data1/orchestrator/vo
```

The message is cut mid-path, losing the actual root cause.

Impact

NFS volume mount failures are a concrete example. The full error body from envd is ~300 characters:

```
failed to mount "7e22c38a-5584-4730-8c31-449f5058ea19": failed to chroot into "/data1/orchestrator/volumes/team-f0796066-fb0b-4ea7-a9fe-613e9b8831bb/vol-885b64ff-686d-4f5c-b16d-eb4d5f9cd577": failed to bind mount "/data1/orchestrator/volumes/team-f0796066-fb0b-4ea7-a9fe-613e9b8831bb/vol-885b64ff-686d-4f5c-b16d-eb4d5f9cd577": no such file or directory
```

At 100 characters the message is truncated to:

```
failed to mount "7e22c38a-5584-4730-8c31-449f5058ea19": failed to chroot into "/data1/orchestrator/vo
```

The operator cannot tell from orchestrator logs or the returned error whether the failure is a missing directory, a permission issue, an NFS timeout, or something else. Diagnosing the root cause requires cross-referencing a completely separate service's logs (the NFS proxy).

Fix

Remove utils.Truncate from the four error-path call sites. envd error response bodies are short diagnostic strings generated by the server, not arbitrary user data, so there is no log-explosion risk.

PR: #3481