refactor: error system cleanup — store separation, DDD fix, test improvements (#10302)

## Summary

Refactors the error system to improve separation of concerns, fix DDD
layer violations, and address code quality issues.

- Extract `missingNodesErrorStore` from `executionErrorStore`, removing
the delegation pattern that coupled missing-node logic into the
execution error store
- Extract `useNodeErrorFlagSync` composable for node error flag
reconciliation (previously inlined)
- Extract `useErrorClearingHooks` composable with explicit callback
cleanup on node removal
- Extract `useErrorActions` composable to deduplicate telemetry+command
patterns across error card components
- Move `getCnrIdFromNode`/`getCnrIdFromProperties` to
`platform/nodeReplacement` layer (DDD fix)
- Move `missingNodesErrorStore` to `platform/nodeReplacement` (DDD
alignment)
- Add unmount cancellation guard to `useErrorReport` async `onMounted`
- Return watch stop handle from `useNodeErrorFlagSync`
- Add `asyncResolvedIds` eviction on `missingNodesError` reset
- Add `console.warn` to silent catch blocks and empty array guard
- Hoist `useCommandStore` to setup scope, fix floating promises
- Add `data-testid` to error groups, image/video error spans, copy
button
- Update E2E tests to use scoped locators and testids
- Add unit tests for `onNodeRemoved` restoration and double-install
guard

Fixes #9875, Fixes #10027, Fixes #10033, Fixes #10085

## Test plan

- [x] Existing unit tests pass with updated imports and mocks
- [x] New unit tests for `useErrorClearingHooks` (callback restoration,
double-install guard)
- [x] E2E tests updated to use scoped locators and `data-testid`
- [ ] Manual: verify error tab shows runtime errors and missing nodes
correctly
- [ ] Manual: verify "Find on GitHub", "Copy", and "Get Help" buttons
work in error cards

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10302-refactor-error-system-cleanup-store-separation-DDD-fix-test-improvements-3286d73d365081838279d045b8dd957a)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

src/components/error/ErrorOverlay.vue

@@ -49,7 +49,12 @@
           <Button variant="muted-textonly" size="unset" @click="dismiss">
             {{ t('g.dismiss') }}
           </Button>
-          <Button variant="secondary" size="lg" @click="seeErrors">
+          <Button
+            variant="secondary"
+            size="lg"
+            data-testid="error-overlay-see-errors"
+            @click="seeErrors"
+          >
             {{
               appMode ? t('linearMode.error.goto') : t('errorOverlay.seeErrors')
             }}