style: fix lint across client packages

eslint --fix autofixes plus manual repairs: max-len line splits
(fake-api handlers, notifier/slots JSDoc, spec signatures), charAt over
non-null-asserted indexing in slash detect/menu cores, Array.from for
code-point capping, typeof assertions for unbound-method in specs,
generic getByRole for the send-button cast, effect disposer void-wrap in
command register, and dropped unused type imports.

packages/host/apiproxy/src/fetch/handler.ts

@@ -96,7 +96,9 @@ function fullResponse(narrow: RpcResponse<unknown>): Response {
 // K appears once in the signature but ties the UNARY_ROUTES[K] row lookup to its own
 // schema/invoke pairing; a union parameter degrades the row to an uninvokable intersection.
 // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-parameters
-async function handleUnary<K extends keyof RpcMethodMap>(api: ApiProxy, method: K, message: ClientRequest, signal: AbortSignal): Promise<Response> {
+async function handleUnary<K extends keyof RpcMethodMap>(
+  api: ApiProxy, method: K, message: ClientRequest, signal: AbortSignal,
+): Promise<Response> {
   const route = UNARY_ROUTES[method]
   const payload = route.schema.safeParse(message.payload)
   if (!payload.success) {

packages/host/apiproxy/tests/api-proxy-cold.spec.ts

@@ -67,7 +67,7 @@ describe('sessions.list cold merge', () => {
     expect(a?.running).toBe(false)
     // Cold summaries are never blank: lazy persistence keeps never-appended
     // sessions out of list(), so a listed session necessarily has events.
-    expect(items.every(item => item.blank === false)).toBe(true)
+    expect(items.every(item => !item.blank)).toBe(true)
     expect(a?.cwd).toBe('/proj')
     expect(a?.parentSessionId).toBeUndefined()
     expect(b?.updatedAt).toBe(2000)