feat(ollama): enhance model pull with improved error handling, persistence, and UI

- Add catalog metadata lookup for better error messages with hints (e.g., for missing manifests or tags)
- Persist downloaded model references in saved remote models for future reuse
- Replace searchRemoteModels import with getSavedRemoteModels in search route
- Enhance pull progress UI to display download bytes, digest, and fallback message when data is unavailable
- Improve error payload with model details, URL, and tags count to guide users toward valid tags or models

lib/user-remote-models.ts

@@ -0,0 +1,62 @@
+import fs from "node:fs/promises";
+import path from "node:path";
+
+export type SavedRemoteModel = {
+  name: string; // full ref, e.g., owner/model:tag or model:tag
+  description?: string;
+  url?: string;
+  tags_count?: number;
+  installed?: boolean;
+  lastUsedAt?: string; // ISO
+};
+
+type SavedRemoteFile = {
+  models: SavedRemoteModel[];
+};
+
+function getFilePath() {
+  return path.join(process.cwd(), "database", "user-remote-models.json");
+}
+
+async function ensureFile(): Promise<void> {
+  const file = getFilePath();
+  try {
+    await fs.access(file);
+  } catch {
+    const initial: SavedRemoteFile = { models: [] };
+    await fs.mkdir(path.dirname(file), { recursive: true });
+    await fs.writeFile(file, JSON.stringify(initial, null, 2), "utf-8");
+  }
+}
+
+export async function getSavedRemoteModels(): Promise<SavedRemoteModel[]> {
+  await ensureFile();
+  const raw = await fs.readFile(getFilePath(), "utf-8");
+  try {
+    const json = JSON.parse(raw) as SavedRemoteFile;
+    return Array.isArray(json.models) ? json.models : [];
+  } catch {
+    return [];
+  }
+}
+
+export async function addSavedRemoteModel(entry: SavedRemoteModel): Promise<void> {
+  await ensureFile();
+  const current = await getSavedRemoteModels();
+  const nowIso = new Date().toISOString();
+  const idx = current.findIndex((m) => m.name === entry.name);
+  const merged: SavedRemoteModel = {
+    ...entry,
+    installed: entry.installed ?? false,
+    lastUsedAt: entry.lastUsedAt ?? nowIso,
+  };
+  if (idx >= 0) {
+    current[idx] = { ...current[idx], ...merged, lastUsedAt: nowIso };
+  } else {
+    current.unshift(merged);
+  }
+  const toWrite: SavedRemoteFile = { models: current.slice(0, 500) };
+  await fs.writeFile(getFilePath(), JSON.stringify(toWrite, null, 2), "utf-8");
+}
+
+