fix: add context.Canceled checks to get-details and get-versions handlers

[friendlygeorge]

Summary

#1335 fixed the list-servers endpoint to return 499 instead of 500 when the client disconnects mid-request. But the get-server-details and get-server-versions handlers still use raw huma.Error500InternalServerError without checking for context.Canceled.

This PR applies the same cancellation check pattern to both remaining GET handlers, so all server endpoints consistently return 499 on client disconnect instead of logging a noisy 500 and triggering superfluous response.WriteHeader warnings.

Changes

• internal/api/handlers/v0/servers.go: Added context.Canceled check before logging and returning 500 in get-server-details (line ~188) and get-server-versions (line ~218)
• Pattern matches ListServersError in list_errors.go (already tested)

Why this matters

Without this fix, clients that disconnect during get-details or get-versions requests still produce:

1. Error-level log lines for benign cancellations (noise in logs/alerts)
2. superfluous response.WriteHeader warnings (huma tries to write to a closed socket)

The fix short-circuits before the error log and 500 response, returning 499 instead.

Test plan

• Existing tests pass (go test ./internal/api/handlers/v0/...)
• Manual: curl --max-time 0.05 http://localhost:8080/v0/servers/<name>/versions/latest no longer logs error-level cancellation

[friendlygeorge]

Hi! This PR adds context.Canceled checks to the get-details and get-versions handlers. When the context is canceled (e.g., user interrupts), the handlers now return cleanly instead of proceeding with stale state.

This has been open for 5 days — let me know if there's anything you'd like me to adjust.