Two client-level paths in the LSP tool bypassed the combined tool-timeout/
caller abort signal built in `LspTool.execute`, so a wedged server hung
past the advertised tool deadline and past user cancellation:
- `getOrCreateClient` took no `AbortSignal` and its `initialize`
`sendRequest` was invoked with `signal = undefined`. With no signal
and no explicit `timeoutMs`, `sendRequest` fell back to the hard-coded
`DEFAULT_REQUEST_TIMEOUT_MS = 30000` internal timer, so a first-use
`lsp` call against a server that wedged in `initialize` ignored the
20s tool default (and any user-supplied shorter `timeout`) until the
30s internal timer fired.
- `writeMessage`/`queueWriteMessage`/`sendNotification` had no timeout
and no signal, so a `textDocument/didOpen`/`didChange`/`didSave` sent
to a server that stopped draining stdin awaited `sink.flush()`
forever. Because writes serialize through `client.writeQueue`, every
later op on the client stalled behind the stuck flush too.
Thread the caller `AbortSignal` through `getOrCreateClient` (initialize
+ initialized notification) and through `sendNotification` /
`queueWriteMessage` / `writeMessage` so the sink flush is raced against
the signal. On abort, tear the client down: kill the process and evict
it from the active-clients map so the next `getOrCreateClient` call
spawns a fresh server instead of queueing behind the wedged sink.
Update the LSP tool callsites and internal helpers
(`captureDiagnosticVersions`, `captureOpenFileVersions`,
`syncFileContent`, `notifyFileSaved`, `formatContent`,
`getDiagnosticsForFile`, `reloadServer`, and the rename didClose /
didRenameFiles path) to forward their operation signal.
Warmup keeps its short explicit `initTimeoutMs` and passes no caller
signal; `sendRequest`'s existing `timeoutMs ?? (signal ? undefined : DEFAULT)`
policy still uses that fixed timer.
Fixes#3962