Simplify health/status responses and upgrade image crate to 0.25

[buzzkillb]

Summary

• Simplify health check endpoint to return only healthy boolean
• Simplify status command display (removed uptime/failures/gateway columns)
• Upgrade image crate from 0.24 to 0.25

Changes

• src/health_server.rs: Simplified health check and connectivity test responses
• src/bot.rs: Simplified status display formatting
• Cargo.toml/Cargo.lock: image crate upgrade

Note

Low Risk

Overview
This pull request simplifies the health check endpoint to return only a healthy boolean, removing the more detailed connectivity test responses. The status command display has been streamlined with the removal of uptime, failures, and gateway columns from the output. The image crate dependency has been upgraded from version 0.24 to 0.25, and the charting module has been updated accordingly to accommodate the API changes.

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