wip: context-meter + model-label UI and provider/inference tweaks

Checkpoint of in-flight work so the orchestrator branch can rebase onto a
clean main: ContextBar → ContextMeter, model-label helper, model/agent picker
+ provider-snapshot/registry changes, inference payload + message-columns.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/coder/src/services/provider-snapshot.ts

@@ -34,7 +34,14 @@ export async function fetchLlamaSwapModels(config: Config): Promise<ProviderMode
     const res = await fetch(`${config.LLAMA_SWAP_URL}/v1/models`);
     if (!res.ok) return [];
     const parsed = (await res.json()) as { data?: Array<{ id: string }> };
-    return (parsed.data ?? []).map((m) => ({ id: m.id, label: m.id }));
+    const models = (parsed.data ?? []).map((m) => ({ id: m.id, label: m.id }));
+    // Hoist the configured DEFAULT_MODEL to the front so the BooCoder picker —
+    // which defaults to models[0] (no isDefault on llama-swap entries) — selects
+    // the same model the dispatcher falls back to. Rest keep llama-swap's order.
+    const def = config.DEFAULT_MODEL;
+    const i = models.findIndex((m) => m.id === def);
+    if (i > 0) models.unshift(models.splice(i, 1)[0]!);
+    return models;
   } catch {
     return [];
   }