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/config.ts

@@ -11,6 +11,7 @@ export class Config {
   shopifyCountryCodeOfOrigin: string
   shopifyProvinceCodeOfOrigin: string
   salesSyncFrequency: number
+  googlePickerApiKey: string
 
   constructor() {
     let ss = SpreadsheetApp.getActive()
@@ -77,5 +78,11 @@ export class Config {
       "value"
     )
     this.salesSyncFrequency = freq ? parseInt(freq) : 10
+    this.googlePickerApiKey = vlookupByColumns(
+      "vars",
+      "key",
+      "googlePickerApiKey",
+      "value"
+    )
   }
 }