Add stake presets (25% / 50% / Max) to prediction controls

[josephchimebuka]

Scope

• Quick-fill buttons based on wallet/vXLM balance
• Clamp to available balance

Acceptance criteria

• Presets disabled when disconnected / zero balance
• Updates stake input accessibly

Files

• src/components/PredictionControls.tsx, BetModal.tsx

[Adiz4415]

@Adiz4415 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

i would love to work on this issue, please assign to me

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Adiz4415 to this issue.

[pre-cious-Igwealor]

@pre-cious-Igwealor has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

can i work on this ?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @pre-cious-Igwealor to this issue.

[angoesther-ops]

@angoesther-ops has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi Maintainer Kindly Assign This To Me

ℹ️ Repo Maintainers: To accept this application, review their application or assign @angoesther-ops to this issue.