Update all go-zero examples to Go 1.21 and go-zero v1.9.1

[Copilot]

• [x] Initial plan created
• [x] Update main repository go.mod to use go-zero v1.9.1
• [x] Update all HTTP examples (9 modules)
• [x] Update all logging examples (6 modules)
• [x] Update other examples (8 modules)
• [x] Run go mod tidy for all modules
• [x] Verify changes - all 24 go.mod files now use v1.9.1
• [x] Fix lint errors in load/main.go for NewRollingWindow API changes
• [x] Clean up accidentally committed binary
• [x] Fix build errors in logging examples (fileconsole, logrus, zerolog)

Created from VS Code via the GitHub Pull Request extension.

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