v0.7.5 — convergence coordinator + credential broker (verb-gated skeleton)

Convergence: crash-safe cross-repo coordinator + credential broker (verb-gated skeleton)

• Panel-ratified convergence coordinator (phase_loop_runtime/convergence/**): frozen contracts
  (event schema, result envelope, provider completion-contract matrix + terminal-outcome state machine,
  broker verb/admission, reconciliation authority-split, resource-isolation predicate, shared
  admission/fencing binding), an append-only event log + exact-state reconciliation, bounded
  codex/claude/outside-agent adapters, advisor-seat lifecycle, and transcript-free status.
• Single credential-capable broker epoch (convergence/broker/**): linearizable admission,
  terminal effect/no-effect evidence with permanent fail-closed on outcome_ambiguous_blocked
  (no timeout/override escape), canonical (repo,branch,head_sha) idempotency, and
  publish_committed_branch with real exact-published-head verification (git ls-remote +
  gh pr list --json headRefOid; any read-failure/mismatch fails closed, never fabricates success).
• Adversarial fault suite (crash/partition/stale-worker/delayed-commit/mixed-version/exact-head/
  outside-agent-adversarial) proving crash-safety + fail-closed behaviour before any enablement.
• Live automation stays DISABLED: every provider verb is classified HUMAN_EXECUTED, so the broker
  refuses all mutations. This ships the live-capable, verb-gated enforcement skeleton; flipping verbs
  to SUPPORTED (live GitHub mutation) is a separate, explicitly-authorized step.
• Fixes: untrack + gitignore .dev-skills/handoffs (tracking broke governed closeouts with
  dirty_worktree_conflict).