feat(sidebar B.1 #31): visible LLM status chip with live state

The LLM runtime has been quiet since it shipped in Phase 3 — users
had no surface-level signal that cleanup was loaded, warming, or
actively generating. Settings has verbose status text internally,
but a dictation-flow user never opens Settings during a run.

New: a shared $state store drives a small chip in the sidebar that
reflects the true LLM state in ≤500 ms of any transition (brief
item #31 acceptance). Five states:

  off        → hidden (user has aiTier === "off")
  warming    → model download or first load in flight; amber pulse
  ready      → loaded + idle; green dot
  generating → cleanup_transcript_text_cmd or
               extract_tasks_from_transcript_cmd in flight; accent
               pulse with Sparkles icon
  error      → last operation failed; red dot with AlertTriangle

The store exposes three calls: refreshLlmStatus(aiTier) (polls the
backend), markGenerating(detail) / markGenerationDone(success).
DictationPage wraps its cleanup + extract calls in mark-generating
pairs. SettingsPage's LLM load / unload / delete / download paths
also refresh the global store so Settings-initiated transitions
surface in the sidebar immediately. The chip collapses to a
dot-only compact form when the sidebar is collapsed.

No backend changes — everything wires onto the existing
`get_llm_status` Tauri command.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/pages/DictationPage.svelte

@@ -5,6 +5,7 @@
   import { emit } from "@tauri-apps/api/event";
   import { getCurrentWindow } from "@tauri-apps/api/window";
   import { page, settings, templates, profiles, addToHistory, addTask, tasks } from "$lib/stores/page.svelte.js";
+  import { markGenerating, markGenerationDone } from "$lib/stores/llmStatus.svelte.js";
   import { profilesStore } from "$lib/stores/profiles.svelte.ts";
   import { toasts } from "$lib/stores/toasts.svelte.js";
   import Card from "$lib/components/Card.svelte";
@@ -444,14 +445,20 @@
     const llmLoaded = await invoke("get_llm_status").catch(() => false);
     if (!llmLoaded) return text;
 
+    // Flip the sidebar LLM status chip to "generating" so the user can
+    // see the cleanup pass in flight (brief item #31). Always paired
+    // with markGenerationDone below — success or failure.
+    markGenerating("Cleaning up");
     try {
       const cleaned = await invoke("cleanup_transcript_text_cmd", {
         transcript: text,
         profileId: profilesStore.activeProfileId,
       });
+      markGenerationDone(true);
       return cleaned?.trim() ? cleaned.trim() : text;
     } catch (err) {
       console.warn("LLM cleanup failed, keeping existing transcript", err);
+      markGenerationDone(false, typeof err === "string" ? err : err?.message ?? null);
       return text;
     }
   }
@@ -459,11 +466,14 @@
   async function extractTasksForTranscript(text) {
     const llmLoaded = await invoke("get_llm_status").catch(() => false);
     if (settings.aiTier === "tasks" && llmLoaded) {
+      markGenerating("Extracting tasks");
       try {
         const items = await invoke("extract_tasks_from_transcript_cmd", { transcript: text });
+        markGenerationDone(true);
         return items.map((taskText) => ({ text: taskText }));
       } catch (err) {
         console.warn("LLM extract_tasks failed, falling back to regex", err);
+        markGenerationDone(false, typeof err === "string" ? err : err?.message ?? null);
       }
     }