Reload the development server after code changes #125

Description

Watch relevant project files and restart/rebuild the local server automatically during development.

Main exposes serve and delegates to provider-specific CLI commands. No shared file watcher/reload orchestration is present; Spin watch declarations do not provide a portable EdgeZero development workflow.

Steps to reproduce

1. Inspect ServeArgs, CLI serve dispatch and the Axum development runner.
2. Compare provider-specific watch support with a documented rebuild/restart workflow for application source changes.

Expected behavior

The developer can enable a documented watch mode and receive a restarted server after successful source changes.

Impact

Developers must stop and rebuild/restart manually or install their own watcher.

Proposed fix

Add a small watch/restart mode that uses native provider watch support where appropriate and provides a clear native/Axum rebuild path.

Done when

• Relevant source/manifest changes trigger rebuild and restart in the supported development modes.
• Generated/build-output files do not cause restart loops.
• Build failures remain visible and shutdown/restart cleans up the previous process.
• Help and documentation identify supported adapters and invocation.

Related

• Parent: Complete CLI and local developer workflows #124.
• CLI command surface
• Axum dev-server runner
• Spin template watch declaration