feat(media): implement integrated media manager with sidebar and picker

- Implement DriveService and ShopifyMediaService for backend operations
- Create MediaSidebar.html with premium UI and auto-polling
- Integrate Google Picker API for robust file selection
- Orchestrate sync logic via MediaService (Drive -> Staged Upload -> Shopify)
- Add secure config handling for API keys and tokens
- Update ppsscript.json with required OAuth scopes
- Update MEMORY.md and README.md with architecture details

src/mediaHandlers.ts

@@ -0,0 +1,122 @@
+import { GASSpreadsheetService } from "./services/GASSpreadsheetService"
+import { GASDriveService } from "./services/GASDriveService"
+import { ShopifyMediaService } from "./services/ShopifyMediaService"
+import { GASNetworkService } from "./services/GASNetworkService"
+import { MediaService } from "./services/MediaService"
+import { Shop } from "./shopifyApi"
+import { Config } from "./config"
+import { Product } from "./Product"
+
+export function showMediaSidebar() {
+  const html = HtmlService.createHtmlOutputFromFile("MediaSidebar")
+    .setTitle("Media Manager")
+    .setWidth(350);
+  SpreadsheetApp.getUi().showSidebar(html);
+}
+
+export function getSelectedSku(): string | null {
+  const ss = new GASSpreadsheetService()
+  const sheet = SpreadsheetApp.getActiveSheet()
+  if (sheet.getName() !== "product_inventory") return null
+
+  const row = sheet.getActiveRange().getRow()
+  if (row <= 1) return null // Header
+
+  const sku = ss.getCellValueByColumnName("product_inventory", row, "sku")
+  return sku ? String(sku) : null
+}
+
+export function getPickerConfig() {
+  const config = new Config()
+  return {
+    apiKey: config.googlePickerApiKey,
+    token: ScriptApp.getOAuthToken(),
+    email: Session.getEffectiveUser().getEmail(),
+    parentId: config.productPhotosFolderId // Root folder to start picker in? Optionally could be SKU folder
+  }
+}
+
+export function getMediaForSku(sku: string): any[] {
+  const config = new Config()
+  const driveService = new GASDriveService()
+
+  try {
+      const folder = driveService.getOrCreateFolder(sku, config.productPhotosFolderId)
+      const files = driveService.getFiles(folder.getId())
+
+      return files.map(f => {
+          let thumb = ""
+          try {
+              const bytes = f.getThumbnail().getBytes()
+              thumb = "data:image/png;base64," + Utilities.base64Encode(bytes)
+          } catch (e) {
+              console.log(`Failed to get thumbnail for ${f.getName()}`)
+              // Fallback or empty
+          }
+          return {
+              id: f.getId(),
+              name: f.getName(),
+              thumbnailLink: thumb
+          }
+      })
+  } catch (e) {
+      console.error(e)
+      return []
+  }
+}
+
+export function saveFileToDrive(sku: string, filename: string, mimeType: string, base64Data: string) {
+  const config = new Config()
+  const driveService = new GASDriveService()
+
+  const folder = driveService.getOrCreateFolder(sku, config.productPhotosFolderId)
+  const blob = Utilities.newBlob(Utilities.base64Decode(base64Data), mimeType, filename)
+
+  driveService.saveFile(blob, folder.getId())
+
+  // Auto-sync after upload?
+  // syncMediaForSku(sku) // Optional: auto-sync
+}
+
+// Picker Callback specific handler if needed, or we just rely on frontend passing back file ID
+// Implementing a "copy from Picker" handler
+export function importFromPicker(sku: string, fileId: string, mimeType: string) {
+    const config = new Config()
+    const driveService = new GASDriveService()
+
+    // Check if file is already in our folder structure?
+    // If user picks from "Photos", it's a separate Blob. We might need to copy it to our SKU folder.
+    // Use DriveApp to get the file (if we have permissions) and make a copy.
+
+    console.log(`Importing ${fileId} for ${sku}`)
+    const file = DriveApp.getFileById(fileId) // Assuming we have scope
+    const folder = driveService.getOrCreateFolder(sku, config.productPhotosFolderId)
+
+    file.makeCopy(file.getName(), folder)
+}
+
+export function syncMediaForSku(sku: string) {
+  const config = new Config()
+  const driveService = new GASDriveService()
+  const shop = new Shop()
+  const shopifyMediaService = new ShopifyMediaService(shop)
+  const networkService = new GASNetworkService()
+
+  const mediaService = new MediaService(driveService, shopifyMediaService, networkService, config)
+
+  // Need Shopify Product ID
+  // We can get it from the Product class or Sheet
+  const product = new Product(sku)
+  if (!product.shopify_id) {
+      product.MatchToShopifyProduct(shop)
+  }
+
+  if (!product.shopify_id) {
+      throw new Error("Product not found on Shopify. Please sync product first.")
+  }
+
+  mediaService.syncMediaForSku(sku, product.shopify_id)
+
+  // Update thumbnail in sheet
+  // TODO: Implement thumbnail update in sheet if desired
+}