Show ASF IDs on STV ballots

[tisonkun]

This resolves #93.

This patch is driven by Codex while I do an overall review that it generally looks good.

[Copilot]

Pull request overview

This PR implements “STV KV v2” candidate metadata to carry ASF IDs alongside display names, and updates the voting UI to show ASF IDs on STV ballots.

Changes:

• Add version: 2 STV KV support where labelmap values are [asfid, name] pairs, with normalization via get_candidates().
• Render ASF IDs in the STV ballot UI and embed {label, asfid, name} candidate objects into the page.
• Update tests/coverage scaffolding and sample election YAML to exercise and document the v2 format.

Reviewed changes

Copilot reviewed 5 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
v3/tests/test_stv.py	Adds unit tests for get_candidates() and verifies tally behavior across kv versions.
v3/tests/check_coverage.py	Updates coverage test election to use STV kv v2 labelmap pairs.
v3/steve/vtypes/stv.py	Introduces get_candidates() and updates STV tally logic to consume versioned candidate metadata.
v3/steve/election.py	Comment formatting only (no behavior change).
v3/server/templates/vote-on.ezt	Embeds ASF IDs into client-side STV candidate data and displays them in the ballot UI.
v3/server/pages.py	Uses get_candidates() to populate normalized STV candidates for the vote-on page.
v3/server/bin/tally.py	Formatting-only changes.
v3/server/bin/election.yaml.sample	Updates sample STV configuration to kv v2 [ASF ID, name] pairs.
v3/server/bin/create-election.py	Validates STV candidate kv structure via get_candidates().

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[tisonkun]

This seems a new feature that we may handle in a follow-up PR.