feat(detection): implement multi-page token detection system

- Add extractTwitterTokens() to detect $TOKEN mentions (e.g., $BONK, $SOL)
- Add extractContractAddresses() for Solana (base58) and Ethereum (0x) addresses
- Add extractTradingPairs() to detect TOKEN/SOL, TOKEN/USDT patterns
- Update extractPageContext() to use new detection functions
- Add detectedTokens field to PageContext interface
- Create DetectedTokensList component to display detected tokens
- Integrate DetectedTokensList into ChatInterface
- Add handleDetectedTokenClick to analyze selected tokens
- Support auto-detection on Twitter, generic pages, and DexScreener

Implements Task 2: Multi-Page Token Detection
Part of hybrid token detection system (manual search + auto-detect)

surfsense_browser_extension/sidepanel/context/PageContextProvider.tsx

@@ -23,6 +23,8 @@ export interface PageContext {
     title: string;
     pageType: PageType;
     tokenData?: TokenData;
+    /** Detected tokens from page content (Twitter mentions, addresses, pairs) */
+    detectedTokens?: TokenData[];
 }
 
 interface PageContextValue {