fix: harden numeric JSON parsing for int/double payloads

[CharlVS]

Summary

• replace fragile as int / as int? JSON casts with num-aware parsing across SDK parsers
• handle mixed numeric payloads (10 vs 10.0) in RPC, CEX market data, JS wrapper, and build-transformer models
• prevent runtime type-cast failures like Type 'double' is not a subtype of type 'int?' in type cast

Scope

• komodo_defi_rpc_methods: rational/history target/trade preimage numeric parsing
• komodo_defi_types: fee-related model parsing
• komodo_cex_market_data: Binance + CoinGecko numeric fields
• komodo_defi_framework: web JS wrapper int return coercion
• komodo_wallet_build_transformer: GitHub API model numeric fields

Notes

• no behavior change intended besides robust numeric coercion during deserialization
• touched files were formatted with dart format

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, you can upgrade your account or add credits to your account and enable them for code reviews in your settings.

[github-actions]

Visit the preview URL for this PR (updated for commit 2ef9a78):

https://komodo-playground--pr336-fix-harden-json-num-aimmbi8m.web.app

_{(expires Mon, 30 Mar 2026 17:09:12 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

_{Sign: 2bfedd77fdea45b25ba7c784416e81f177aa5c47}