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/client/runtime/tests/fake-api.ts

@@ -110,9 +110,12 @@ export class FakeApiClient implements IApiClient {
   // Payloads stay `unknown` (lint-lane note above); response rows are the real
   // wire shapes so cases can program requires-bearing catalogs and dual-address
   // skill lists without casts.
-  onCommandList: (payload: unknown) => Promise<RpcResponse<{ commands: CommandDescriptor[] }>> = () => Promise.resolve(ok({ commands: [] }))
-  onCommandExecute: (payload: unknown) => Promise<RpcResponse<{ matched: boolean; result?: CommandExecuteResult }>> = () => Promise.resolve(ok({ matched: false }))
-  onSkillList: (payload: unknown) => Promise<RpcResponse<{ skills: SkillEntry[] }>> = () => Promise.resolve(ok({ skills: [] }))
+  onCommandList: (payload: unknown) => Promise<RpcResponse<{ commands: CommandDescriptor[] }>>
+    = () => Promise.resolve(ok({ commands: [] }))
+  onCommandExecute: (payload: unknown) => Promise<RpcResponse<{ matched: boolean; result?: CommandExecuteResult }>>
+    = () => Promise.resolve(ok({ matched: false }))
+  onSkillList: (payload: unknown) => Promise<RpcResponse<{ skills: SkillEntry[] }>>
+    = () => Promise.resolve(ok({ skills: [] }))
 
   readonly commands: IApiClient['commands'] = {
     list: (payload: unknown) => this.record('command.list', payload, this.onCommandList(payload)),