feat(FN-2591): add Bedrock provider icon support

- Add a dedicated Bedrock SVG provider icon and provider token styling
- Wire Bedrock provider aliases so provider detection resolves to the new icon key
- Update usage indicator mapping so Bedrock usage providers render the correct icon
- Expand ProviderIcon tests to cover Bedrock icon rendering and alias coverage

packages/dashboard/app/styles.css

@@ -169,6 +169,7 @@
   --provider-minimax: #e73562;
   --provider-zai: #1a6dff;
   --provider-kimi: #6c5ce7;
+  --provider-bedrock: #ff9900;
   --provider-opencode: #38bdf8;
   --provider-icon-contrast: var(--bg);