refactor appState and proxy

[ChuckHend]

• separate the proxy logic from server
• move cache update process into its own module
• creates appState struct

[Copilot]

Pull Request Overview

This PR refactors the application state management and proxy logic to improve code organization and maintainability. The main goals are separating concerns between server, proxy, and cache management components.

• Creates a centralized AppState struct to hold shared application state including database pools, job cache, and worker health monitoring
• Extracts proxy startup logic from main.rs into the proxy module for better separation of concerns
• Moves cache synchronization functionality into a dedicated cache module

Reviewed Changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
server/src/app_state.rs	New module defining AppState struct with initialization logic
server/src/cache.rs	New module containing job cache management and sync functionality
server/src/main.rs	Simplified main function using AppState, moved proxy logic to proxy module
server/src/routes/*.rs	Updated route handlers to use AppState instead of individual dependencies
proxy/src/proxy.rs	Added start_postgres_proxy function moved from main.rs
extension/src/*.rs	Minor code cleanup removing deprecated functions and dead code

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