chore(frontend): remove BadgeRegistry V1 retro-compat after V2 redeploy

[V-Vaal]

Context

Temporary frontend retro-compat logic was introduced in PR #158 to support mixed
BadgeRegistry deployments (V1 using bytes32, V2 using bytes).

This includes V1 ABI usage, version probing, conditional decoding and write fallbacks.

Goal

Once the BadgeRegistry V2 is fully redeployed and becomes the only supported version, remove all V1-related frontend code paths.

Cleanup tasks

• Remove V1 ABI and related imports
• Remove version probe and decode-error-based detection
• Remove conditional ABI selection and decoding
• Remove V1 write fallback logic
• Simplify badge read/write paths to V2-only

Notes

This issue tracks technical debt only and should be addressed after confirming all environments/networks use the V2 registry.