feat(speech): add prompt voice input (#249)

## Summary
- add server-backed speech capabilities and transcription endpoints plus
UI settings for speech configuration
- add push-to-talk prompt voice input with microphone controls,
transcription insertion, and browser capability gating
- keep prompt controls aligned by restoring right-side nav placement and
moving the mic beside the expand control

packages/ui/src/stores/speech.ts

@@ -0,0 +1,46 @@
+import { createSignal } from "solid-js"
+import type { SpeechCapabilitiesResponse } from "../../../server/src/api-types"
+import { serverApi } from "../lib/api-client"
+import { getLogger } from "../lib/logger"
+
+const log = getLogger("api")
+
+const [speechCapabilities, setSpeechCapabilities] = createSignal<SpeechCapabilitiesResponse | null>(null)
+const [speechCapabilitiesLoading, setSpeechCapabilitiesLoading] = createSignal(false)
+const [speechCapabilitiesError, setSpeechCapabilitiesError] = createSignal<string | null>(null)
+
+let speechCapabilitiesPromise: Promise<SpeechCapabilitiesResponse | null> | null = null
+
+async function loadSpeechCapabilities(force = false): Promise<SpeechCapabilitiesResponse | null> {
+  if (!force && speechCapabilities()) return speechCapabilities()
+  if (speechCapabilitiesPromise) return speechCapabilitiesPromise
+
+  setSpeechCapabilitiesLoading(true)
+  setSpeechCapabilitiesError(null)
+  speechCapabilitiesPromise = serverApi
+    .fetchSpeechCapabilities()
+    .then((result) => {
+      setSpeechCapabilities(result)
+      setSpeechCapabilitiesError(null)
+      return result
+    })
+    .catch((error) => {
+      log.error("Failed to load speech capabilities", error)
+      setSpeechCapabilities(null)
+      setSpeechCapabilitiesError(error instanceof Error ? error.message : String(error))
+      return null
+    })
+    .finally(() => {
+      setSpeechCapabilitiesLoading(false)
+      speechCapabilitiesPromise = null
+    })
+
+  return speechCapabilitiesPromise
+}
+
+function resetSpeechCapabilities(): void {
+  setSpeechCapabilities(null)
+  setSpeechCapabilitiesError(null)
+}
+
+export { speechCapabilities, speechCapabilitiesLoading, speechCapabilitiesError, loadSpeechCapabilities, resetSpeechCapabilities }