Fix resource refresh button not triggering re-fetch

[olaservo]

Summary

Fixes #1120

• The readResource function had an early return when the resource URI was already in resourceContentMap, which prevented the Refresh button from ever re-fetching
• Added a { bypassCache } options parameter to readResource to skip the cache when the Refresh button is clicked
• When not bypassing cache, cached content is now properly synced to the display (fixes switching between previously viewed resources showing stale content)
• Errors from failed resource reads are no longer cached, so re-clicking a resource will retry instead of serving a stale error

Changes

• client/src/App.tsx — Added { bypassCache } options parameter to readResource; stopped caching errors in resourceContentMap; forwarded options through the prop wrapper
• client/src/components/ResourcesTab.tsx — Updated type signature; Refresh button now passes { bypassCache: true }

Test plan

• Existing unit tests pass
• TypeScript type-check passes (npx tsc --noEmit)
• Build passes (npm run build-client)
• Lint passes (npm run lint)
• Manual verification: connect to an MCP server, click a resource, click Refresh → new request appears in history
• Manual verification: click resource A, click resource B, click resource A again → correct cached content displays
• Manual verification: simulate a failed resource read, then re-click → resource is retried instead of showing stale error

🦉 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes resource re-fetch behavior in the client by adding a bypassCache option to readResource, ensuring the Refresh button triggers a new server request and cached content is correctly synced to the UI when revisiting previously viewed resources.

Changes:

• Add { bypassCache } option to readResource and use it to bypass cache on Refresh.
• Sync cached resource content to the display instead of early-returning without updating UI state.
• Stop caching read errors in resourceContentMap (intended to ensure retries on re-click).

Reviewed changes

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

File	Description
client/src/App.tsx	Adds bypassCache support to readResource, updates caching/refresh logic, and forwards options through the ResourcesTab prop wrapper.
client/src/components/ResourcesTab.tsx	Updates readResource prop signature and passes { bypassCache: true } from the Refresh button.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

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[Copilot]

Because resourceErrorMap[uri] is only cleared on success, any retry attempt will continue to have an error entry until the request completes. Since some UI paths render resourceError in preference to cached content, this can leave a stale error visible while the retry is in-flight. Consider clearing resourceErrorMap[uri] when starting a new read (after passing the cache check / before sending the request), not only when a read succeeds.

Suggested change

	setResourceErrorMap((prev) => {
	if (!hasOwn.call(prev, uri)) return prev;
	const next = { ...prev };
	delete next[uri];
	return next;
	});