feat: upgrade to Go 1.25.3 and update build to include api-gateway

- Create ADR-0034 documenting Go version upgrade to 1.25.3
- Mark ADR-0002 as superseded by ADR-0034
- Update CI workflow to use Go 1.25.3
- Update Makefile to build both platform and api-gateway binaries
- Update CI workflow to build and upload both binaries
- Update documentation (ADR README and mkdocs.yml) to include ADR-0034

docs/content/adr/README.md

@@ -23,7 +23,8 @@ Each ADR follows this structure:
 ### Epic 0: Project Setup & Foundation
 
 - [ADR-0001: Go Module Path](./0001-go-module-path.md) - Module path: `git.dcentral.systems/toolz/goplt`
-- [ADR-0002: Go Version](./0002-go-version.md) - Go 1.24.3
+- [ADR-0002: Go Version](./0002-go-version.md) - Go 1.24.3 (Superseded by ADR-0034)
+- [ADR-0034: Go Version Upgrade to 1.25.3](./0034-go-version-upgrade.md) - Go 1.25.3
 - [ADR-0003: Dependency Injection Framework](./0003-dependency-injection-framework.md) - uber-go/fx
 - [ADR-0004: Configuration Management](./0004-configuration-management.md) - spf13/viper + cobra
 - [ADR-0005: Logging Framework](./0005-logging-framework.md) - go.uber.org/zap