Desktop "Add server" dialog: Server name / Username / Password fields cannot be edited (only Server address works) — v1.18.4 #38193

Description

In Desktop → Settings → Server → Servers → "Add server", the dialog has 4 fields:
Server address, Server name (optional), Username (optional), Password (optional).

Only Server address is actually editable. The other three are stuck showing their
placeholder text and cannot be typed into, no matter how they're focused.

Steps to reproduce

1. Open Desktop → Settings → Server → Servers → "+ Add server" → "Add server"
2. Click into "Server address", type a URL — works fine, text appears.
3. Click into "Server name (optional)", type any text — nothing appears, field still shows
   the "Localhost" placeholder.
4. Click into "Username (optional)", type text — same issue. (Slightly confusing to spot
   because the placeholder example text is literally "opencode", so it can look like it
   accepted input at a glance — it didn't.)
5. Triple-click to select-all in "Username", type replacement text — still doesn't change,
   confirming the field isn't accepting input at all, not just failing to clear first.
6. Click into "Password (optional)", type text — same issue, placeholder "password" never
   goes away.

Impact

Makes it impossible to add a remote server that needs a name, username, or password —
e.g. connecting to a self-hosted opencode serve instance on a VPS protected by basic auth.
Only unauthenticated / unnamed servers can be added through this dialog at all.

Environment

• OpenCode Desktop v1.18.4, Windows