feat: implement bridged asset canonical detection and UI improvements

**Bridged Asset Canonical Detection:**
- Add BRIDGED_CATEGORY_MAPPINGS for 6 Ethereum canonicals (WBTC, WETH, WSTETH, USDC, USDT, DAI)
- Implement three-way canonical detection via CoinGecko:
  1. Check if asset IS canonical (processes ETH WBTC/USDC/USDT directly)
  2. Check if coinId in bridged category (catches Arbitrum WBTC, Polygon WBTC.E variants)
  3. Check if platforms contains canonical (catches shared coin IDs like USDC/USDT)
- Prioritize CoinGecko over Zerion when Ethereum canonical detected
- Fix length <= 1 edge case to return canonical instead of undefined
- Merge USDT0 into USDT group via bridged-usdt category

**UI Improvements:**
- Deduplicate chain icons in grouped asset rows
- Each chain now appears only once regardless of asset variant count

**Results:**
- ✅ ETH WBTC/WETH/WSTETH/USDC/USDT are primaries (clean "Wrapped Bitcoin" titles)
- ✅ All L2 bridged variants point to Ethereum canonicals
- ✅ USDT0 (Plasma) merged into USDT group as intended
- ✅ No more duplicate chain icons in search results
- ✅ No more ugly "Arbitrum Bridged WBTC" titles

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 (1M context) <[email protected]>

Author: gomesalexandre