fix(data-sources): use official Jam provider logo

[siisee11]

One-Line Summary

Jam now uses its official pink mascot logo instead of the temporary generic video icon everywhere providers are shown.

User-Facing Changes

• Replaces the generic Jam video-camera icon in shared provider UI with the official hosted Jam WebP logo.
• Uses the same shared Jam logo component in the public landing provider catalog.
• Preserves decorative and labelled accessibility behavior for provider icons.

Why This Changed

The initial Jam provider used a generic video symbol because no brand asset was wired into the shared icon system. That made Jam harder to recognize and caused the landing catalog to maintain a separate fallback icon.

How It Changed

• Adds an exported JamIcon component backed by https://storage.googleapis.com/jam-assets/jam-logo.webp.
• Registers JamIcon in the shared provider map.
• Reuses the shared component from the landing brand map and removes the duplicated fallback SVG.
• Adds markup coverage for the official URL, 384×384 view box, and accessible title.

Extra Context / Decisions (Optional)

The supplied asset responds as a 384×384 transparent image/webp with public caching. The component references the canonical hosted asset directly so the provider mark stays identical to Jam's supplied logo.

Verification

• bun run format
• bun run typecheck && bunx vitest run src/data-sources/provider-icons.test.tsx in packages/ui (11 tests)
• bun run typecheck && bunx vitest run src/shared/icons/brands.test.tsx in apps/landing
• bunx oxlint --no-ignore apps/landing/src/shared/icons/brands.tsx packages/ui/src/data-sources/provider-icons.tsx packages/ui/src/data-sources/provider-icons.test.tsx packages/ui/src/icons/jam-icon.tsx
• git diff --check
• curl -fsSI https://storage.googleapis.com/jam-assets/jam-logo.webp

Video / Screenshot (Optional)