[cocvn157]

Adds opt-in HTTP conditional request support (conditional_request: bool = False on HttpFetcherConfig) to HttpFetchProvider and DataUpdater so polling unchanged HTTP data sources uses ETag / If-None-Match and Last-Modified / If-Modified-Since instead of refetching and overwriting the policy store on every interval.

When conditional_request=True, HttpFetchProvider caches response validators per url|dst_path key and returns FETCH_NOT_MODIFIED on 304 Not Modified across both aiohttp and httpx backends, causing DataUpdater to skip _store_fetched_data() and report DataEntryReport(entry=entry, fetched=True, saved=False). Validator caches are cleared on get_base_policy_data() and reset() so initial loads and policy-store resets always perform a full fetch.

Fixes #990

[netlify]

✅ Deploy Preview for opal-docs ready!

Name	Link
🔨 Latest commit	e805c33
🔍 Latest deploy log	https://app.netlify.com/projects/opal-docs/deploys/6aefdc07dacd683eb0c74d13
😎 Deploy Preview	https://deploy-preview-998--opal-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
🤖 Make changes	Run an agent on this branch

---

To edit notification comments on pull requests, go to your Netlify project configuration.