[EPAC-2282]: Fix live vote poller Go module imports

[riddim-developer-bot]

Scope

Fixes the backend Go CI compile failure in backend/live-vote-poller by aligning internal import paths with the module path declared in backend/live-vote-poller/go.mod.

Bugfix SPEC

• Spec: Linear issue EPAC-2282: https://linear.app/riddimsoftware/issue/EPAC-2282/ci-backend-go-tests-failing-on-main
• Trace ID: EPAC-2282

Testing notes

• Automated tests run: go test ./... in backend/live-vote-poller passed.
• Automated tests run: go test -tags=integration ./... in backend/live-vote-poller passed.
• Automated tests run: backend go.work integration loop progressed through backend/live-vote-poller after the fix; later local run stopped at hansard-subjects-index because no local Postgres service was running.
• Skipped check: make -C backend test-integration could not start because Docker daemon is not running locally.
• Manual verification: Not applicable; backend CI-only compile fix.

Screenshots

Not applicable.

Related issue

• Closes: EPAC-2282

Release-Note: Omitted; CI-only backend compile fix with no user-visible behavior change.