feat: port upstream scraper improvements to monorepo

Kijiji improvements:
- Add error classes: NetworkError, ParseError, RateLimitError, ValidationError
- Add exponential backoff with jitter for retries
- Add request timeout (30s abort)
- Add pagination support (SearchOptions.maxPages)
- Add location/category mappings and resolution functions
- Add enhanced DetailedListing interface with images, seller info, attributes
- Add GraphQL client for seller details

Facebook improvements:
- Add parseFacebookCookieString() for parsing cookie strings
- Add ensureFacebookCookies() with env var fallback
- Add extractFacebookItemData() with multiple extraction paths
- Add fetchFacebookItem() for individual item fetching
- Add extraction metrics and API stability monitoring
- Add vehicle-specific field extraction
- Improve error handling with specific guidance for auth errors

Shared utilities:
- Update http.ts with new error classes and improved fetchHtml

Documentation:
- Port KIJIJI.md, FMARKETPLACE.md, AGENTS.md from upstream

Tests:
- Port kijiji-core, kijiji-integration, kijiji-utils tests
- Port facebook-core, facebook-integration tests
- Add test setup file

Scripts:
- Port parse-facebook-cookies.ts script

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/core/src/index.ts

@@ -1,8 +1,36 @@
 // Export all scrapers
-export { default as fetchKijijiItems, slugify } from "./scrapers/kijiji";
-export type { KijijiListingDetails } from "./scrapers/kijiji";
+export {
+	default as fetchKijijiItems,
+	slugify,
+	resolveLocationId,
+	resolveCategoryId,
+	buildSearchUrl,
+	extractApolloState,
+	parseSearch,
+	parseDetailedListing,
+	HttpError,
+	NetworkError,
+	ParseError,
+	RateLimitError,
+	ValidationError,
+} from "./scrapers/kijiji";
+export type {
+	KijijiListingDetails,
+	DetailedListing,
+	SearchOptions,
+	ListingFetchOptions,
+} from "./scrapers/kijiji";
 
-export { default as fetchFacebookItems } from "./scrapers/facebook";
+export {
+	default as fetchFacebookItems,
+	fetchFacebookItem,
+	parseFacebookCookieString,
+	ensureFacebookCookies,
+	extractFacebookMarketplaceData,
+	extractFacebookItemData,
+	parseFacebookAds,
+	parseFacebookItem,
+} from "./scrapers/facebook";
 export type { FacebookListingDetails } from "./scrapers/facebook";
 
 export { default as fetchEbayItems } from "./scrapers/ebay";