Add optional file overwrite with webhook response

[Copilot]

Adds OVERWRITE_WITH_RESPONSE flag to enable overwriting watched XML files with webhook server responses. When enabled with INCLUDE_CONTENT=true, the watcher sends file content to the server and replaces the original file with the response.

Implementation

• New environment variable: OVERWRITE_WITH_RESPONSE (default: false)
• Response validation: Requires 2xx status, XML content-type (text/xml or application/xml), non-empty body
• Recursive trigger prevention: Temporary ignore list (2s) prevents self-triggered webhooks after file modification
• Configuration validation: Warns at startup if overwrite enabled without content inclusion

Example Usage

docker run -d \
  -v /path/to/watch:/watch \
  -e WEBHOOK_URL="https://api.example.com/process" \
  -e INCLUDE_CONTENT="true" \
  -e OVERWRITE_WITH_RESPONSE="true" \
  xml-watcher:latest

Server receives XML content in webhook payload, returns transformed XML with Content-Type: application/xml, watcher overwrites original file without triggering new event.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Optional ability to overwrite with response</issue_title>
<issue_description>If enabled with a runtime flag (including send content), the watcher should overwrite the contents of the sent file with the response from the server. Of course, the response content type and status code should align. This should, of course, override the watched file without triggering a new watch event. </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Optional ability to overwrite with response #3

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[Copilot]

Pull request overview

This PR adds an optional file overwrite feature that allows the XML watcher to replace watched files with webhook server responses. When enabled with OVERWRITE_WITH_RESPONSE=true and INCLUDE_CONTENT=true, the watcher sends file content to the webhook server and overwrites the original file with the response if it's valid XML with a 2xx status code.

Key Changes:

• New OVERWRITE_WITH_RESPONSE environment variable enables response-based file overwriting
• Temporary ignore list mechanism (2-second duration) prevents recursive webhook triggers after file modification
• Response validation ensures proper XML content-type and non-empty body before overwriting

Reviewed changes

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

File	Description
src/main.rs	Implements overwrite logic with ignore list for preventing recursive triggers, adds configuration validation
README.md	Documents the new feature with requirements and usage examples

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