Pre-fix TerminalTab tried to open /ws/terminal/<id> for every workspace
including external ones (which have no shell endpoint on the
workspace-server). The server returned 404, status flipped to "error",
the user saw "Connection failed" with a Reconnect button — reading as
a bug when really the runtime intentionally has no TTY.
Now: when data.runtime is in RUNTIMES_WITHOUT_TERMINAL (currently just
"external"), TerminalTab renders a NotAvailablePanel with a big
terminal-off icon and a one-line explanation including the runtime
name. The xterm + WebSocket dance is skipped entirely — no spurious
404s, no scary error UI, no Reconnect that can't help.
The runtime is determined from the data prop now threaded by
SidePanel.tsx (existing pattern for ChatTab/ConfigTab/etc).
Tests: 4 new in TerminalTab.notAvailable.test.tsx pin: external
renders banner with runtime name, external doesn't open WS, claude-
code mounts normally (regression cover for the early-return scope),
data omitted falls through (back-compat).
Build clean. 1258 tests pass.
ba63f76e10