fix(terminals): render readonly session output without a staircase

Readonly sessions aggregated from other devframes via the hub stream their raw output straight to the client, so bare LF line endings never get the server-side CRLF normalization that own pipe sessions receive — xterm then left the cursor column untouched on each newline and rendered a staircase. Enable xterm's convertEol for readonly sessions so a lone LF is treated as CRLF (a no-op when CRLF already arrived); interactive PTY sessions keep it off so full-screen TUIs retain exact cursor control.

Author: antfubot

plugins/terminals/src/client/TerminalView.svelte

@@ -59,6 +59,14 @@
       scrollback: 10000,
       theme: isDark ? DARK_THEME : LIGHT_THEME,
       disableStdin: info.mode !== 'interactive',
+      // Readonly sessions are line-oriented log streams. Own pipe sessions get
+      // their bare `\n` normalized to `\r\n` server-side, but sessions
+      // aggregated from other devframes via the hub stream their raw output
+      // here unfiltered — a lone `\n` would then leave the cursor's column
+      // untouched and render a staircase. `convertEol` makes xterm treat `\n`
+      // as `\r\n`, fixing both (a no-op where CRLF already arrived). Interactive
+      // PTY sessions keep it off so full-screen TUIs control the cursor exactly.
+      convertEol: info.mode !== 'interactive',
       allowProposedApi: false,
     })