RI-8158: vector set similarity thunks and hooks

[dantovska]

What

Adds the FE foundation for the vector-set similarity search feature — Redux state, thunks, and the consumer hook — without yet wiring up any UI components.

• API endpoints: registered VECTOR_SET_SIMILARITY_SEARCH and VECTOR_SET_SIMILARITY_SEARCH_PREVIEW constants.
• Vector-set slice (slices/browser/vectorSet.ts): added two new sub-slices — similaritySearch (results + loading/error) and similaritySearchPreview (BE-built VSIM command preview + loading/error) — with their load*/Success/Failure/clear* actions and selectors. Added the fetchVectorSetSimilaritySearch and fetchVectorSetSimilaritySearchPreview thunks. Both slices share the same payload shape since the FE only fires a preview once the form is valid.
• Interfaces (slices/interfaces/vectorSet.ts): introduced VectorSetSimilaritySearchPayload, VectorSetSimilarityMatch, VectorSetSimilaritySearchResponse, and the matching slice-state + preview types.
• useSimilaritySearch hook: pure form-state → BE-payload mapper plus debounced preview dispatch. Cancels and clears the preview slice when the form state can't map to a valid VSIM payload, and clears both slices when the selected key changes or the consumer unmounts.
• Comprehensive Jest coverage for all of the above (slice reducers/selectors/thunks and every hook branch).
  The form/results components that consume this layer are intentionally not part of this PR — they are coming in a follow-up.

Testing

Following PR

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Note

Medium Risk
Adds new Redux sub-slices and async thunks (including abortable preview requests) plus new hook logic, which can affect browser state management and request lifecycles. Also changes several existing vector-set thunks to fail with a default error message on non-2xx statuses, potentially altering user-visible error handling.

Overview
Lays the FE groundwork for Vector Set similarity search by adding new API endpoints plus Redux state/actions/selectors and thunks to execute similarity search and fetch a debounced, abortable backend-built VSIM command preview.

Introduces useSimilaritySearch (form-state→payload mapping, debounced preview dispatch, and automatic reset on key change/unmount) and useSimilaritySearchResults (exposes matches/hasResults), and exports them from the vector-set hooks index.

Refactors vector parsing helpers by exporting bytesToBase64 and validateVector for reuse, and expands Jest coverage for the new slice logic/thunks/hooks (including abort/cancel behavior).

^{Reviewed by Cursor Bugbot for commit 1ea2152. Bugbot is set up for automated code reviews on this repo. Configure here.}

[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[github-actions]

Code Coverage - Backend unit tests

St.❔	Category	Percentage	Covered / Total
🟢	Statements	92.57%	15553/16802
🟡	Branches	74.67%	4882/6538
🟢	Functions	86.5%	2422/2800
🟢	Lines	92.4%	14869/16092

Test suite run success

3413 tests passing in 306 suites.

Report generated by 🧪jest coverage report action from 1ea2152

[github-actions]

Code Coverage - Integration Tests

Status	Category	Percentage	Covered / Total
🟡	Statements	79.41%	17433/21953
🟡	Branches	61.88%	7967/12874
🟡	Functions	67.89%	2417/3560
🟡	Lines	78.97%	16397/20762

[github-actions]

Code Coverage - Frontend unit tests

St.❔	Category	Percentage	Covered / Total
🟢	Statements	82.66%	24314/29415
🟡	Branches	67.88%	10228/15068
🟡	Functions	77.8%	6555/8425
🟢	Lines	83.13%	23760/28583

Test suite run success

6826 tests passing in 789 suites.

Report generated by 🧪jest coverage report action from 1ea2152

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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^{Reviewed by Cursor Bugbot for commit f78d4a7. Configure here.}