v0.7.1

v0.7.1 — the chain-tier release

The SANTA chain tier went live and donner grew a voting + retargeting arm —
which surfaced four consensus divergences in the voting code it grades, all
JVM-verified and fixed:

• Vote tally is now SEEDED (JVM VotingData parity): only ids the previous
  boundary itself voted accumulate; unseeded votes count for nothing;
  chain-start windows tally empty. The old plain counter could step a
  parameter the JVM doesn't (fork direction; never hit on synced history).
• Approval = closing-epoch count + collected (was collected-only);
  lifecycle reads an original-table snapshot; approved vote for an absent/
  unknown id errors (JVM throw parity); id 9 steppable via votes.
• Soft-fork-voting boundary candidates no longer self-orphan:
  compute_expected_parameters_for_candidate derives the fork vote from the
  candidate's own configured votes instead of a header that isn't in the
  chain yet. mining.votes is live operator config — the governance path
  now actually works for miners.
• Pure consensus seams (seeded tally, boundary parameters, difficulty
  cores) public for conformance: donner chain arm 10/10 on the corpus,
  block tier regression clean.

sigma-rust 1e346127. Addons: indexer 0.2.5, fastsync 0.1.3, lockfiles
synced. 891 workspace tests green.

Full Changelog: v0.7.0...v0.7.1