Fix console errors when clicking Fleet dashboard cards in error state

[Copilot]

Summary

Console errors (Cannot read properties of null) prevented the slide-in panel from opening when clicking Fleet dashboard cards, particularly those in error states.

Occurred changes and/or fixed issues

• Fixed ResourceDetails.vue computed property that assumed targetClusters always exists
• Panel now opens correctly for resources with undefined/null targetClusters

Technical notes summary

The clusters computed property called .map() on potentially undefined this.value.targetClusters. Added defensive check matching the pattern used in ResourceCardSummary.vue:

- return this.value.targetClusters.map((cluster) => ({
+ return (this.value.targetClusters || []).map((cluster) => ({

Areas or cases that should be tested

• Click on Fleet dashboard cards in error states
• Click on cards while resources are still loading
• Verify slide-in panel opens and displays resource details correctly
• Test with both GitRepo and HelmOp resources

Areas which could experience regressions

• Fleet dashboard slide-in panel interactions
• Resource details display for all Fleet resource states

Screenshot/Video

Checklist

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
• The PR has a Milestone
• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes
• The PR has been reviewed in terms of Accessibility
• The PR has considered, and if applicable tested with, the three Global Roles Admin, Standard User and User Base

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Original prompt

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This section details on the original issue you should resolve

<issue_title>There arec console errors in the Fleet dashboard after clicking on a card in an error state</issue_title>
<issue_description><!--------- For bugs and general issues --------->
Setup

• Rancher version: 2.14 (head)
• Rancher UI Extensions: None
• Browser type & version: Chrome

Describe the bug

Console errors in Fleet dashboard after clicking on a card in error state:

entry-helpers.js:40 TypeError: Cannot read properties of null (reading 'emitsOptions')
    at shouldUpdateComponent (runtime-core.esm-bundler.js:6742:1)
    at updateComponent (runtime-core.esm-bundler.js:5279:1)
    at processComponent (runtime-core.esm-bundler.js:5225:1)
    at patch (runtime-core.esm-bundler.js:4730:1)
    at patchBlockChildren (runtime-core.esm-bundler.js:5086:1)
    at Object.process (runtime-core.esm-bundler.js:902:1)
    at patch (runtime-core.esm-bundler.js:4742:1)
    at ReactiveEffect.componentUpdateFn [as fn] (runtime-core.esm-bundler.js:5440:1)
    at ReactiveEffect.run (reactivity.esm-bundler.js:237:1)
    at ReactiveEffect.runIfDirty (reactivity.esm-bundler.js:275:1)

TypeError: Cannot read properties of null (reading 'subTree')
    at getNextHostNode (runtime-core.esm-bundler.js:6024:1)
    at patch (runtime-core.esm-bundler.js:4680:1)
    at patchBlockChildren (runtime-core.esm-bundler.js:5086:1)
    at Object.process (runtime-core.esm-bundler.js:902:1)
    at patch (runtime-core.esm-bundler.js:4742:1)
    at ReactiveEffect.componentUpdateFn [as fn] (runtime-core.esm-bundler.js:5440:1)
    at ReactiveEffect.run (reactivity.esm-bundler.js:237:1)
    at ReactiveEffect.runIfDirty (reactivity.esm-bundler.js:275:1)
    at callWithErrorHandling (runtime-core.esm-bundler.js:199:1)
    at flushJobs (runtime-core.esm-bundler.js:408:1)

To Reproduce

Add a https://github.com/rancher/fleet-examples repo
Go to Fleet Dashboard
Click on the card of that repo

Result
Screen gets a grey popover, but nothing is shown.
Errors are shown in the console.

Expected Result

No errors should be shown

Screenshots

Screen.Recording.2026-01-05.at.4.26.41.PM.mov

Additional context

</issue_description>

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

• Fixes There are console errors in the Fleet dashboard after clicking on a card in an error state #16308

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