fix(verification): keep passed uat results across verifier re-runs

A phase whose human UAT passed could loop forever between execute-phase
and verify-work. A gap-closure plan, or a later phase editing a covered
file, made the report stale; verify-work only recorded a passed UAT
against human_needed; the re-run verifier could not see the UAT file and
re-emitted human_needed; and execute-phase's human_needed branch then
rewrote *-UAT.md with every row back to [pending].

- verification.uat-evidence: recorded UAT rows plus the covered
  implementation files changed since the UAT. The verifier (Step 8b)
  treats a row that passed on unchanged code as verified and re-lists
  only affected rows, each with a retest_reason.
- verification.seed-uat: merges the report's human items into *-UAT.md.
  Existing rows are kept byte-for-byte; a pass is reset only with a
  recorded reason.
- verification.canonicalize-uat: the single human_needed -> passed flip,
  gated on the uat-only row predicate; refuses a stale report.
- verification.status reports stale_reason; init.progress lists every
  executed-but-stale phase in reverify_phases.
- verify-work and progress re-run the verifier themselves for a stale
  report instead of routing to execute-phase; execute-phase records a
  gap-closure checkpoint's UAT answers before dispatching the verifier.

Fail-closed properties are unchanged: a malformed fingerprint and a real
change to covered code still read stale.

Emitted-Drift-Ack-Growth: execute-phase.md — verify_phase_goal gains the gap-closure uat-record pointer and the merge-not-overwrite human_needed branch; the uat template it replaced moved into verification.seed-uat
Emitted-Drift-Ack-Growth: msd-verifier.md — new step 8b pointer to the lazily loaded verifier-uat-evidence reference plus the human_verified frontmatter key
Emitted-Drift-Ack-Growth: progress.md — route v.stale now re-verifies every stale executed phase in place instead of naming one command

tests/fixtures/install-tree/opencode.json

@@ -437,6 +437,7 @@
   "msd-core/references/sketch-variant-patterns.md",
   "msd-core/references/specless-probe-fallback.md",
   "msd-core/references/spidr-splitting.md",
+  "msd-core/references/stale-reverification.md",
   "msd-core/references/tdd.md",
   "msd-core/references/thinking-models-debug.md",
   "msd-core/references/thinking-models-execution.md",
@@ -454,6 +455,7 @@
   "msd-core/references/verification-patterns.md",
   "msd-core/references/verifier-evidence-gate.md",
   "msd-core/references/verifier-phase-gates.md",
+  "msd-core/references/verifier-uat-evidence.md",
   "msd-core/references/verifier-wiring-patterns.md",
   "msd-core/references/verify-command-path-resolvability.md",
   "msd-core/references/verify-mvp-mode.md",
@@ -556,6 +558,7 @@
   "msd-core/workflows/execute-phase/steps/executor-isolation-dispatch.md",
   "msd-core/workflows/execute-phase/steps/executor-progress-policy.md",
   "msd-core/workflows/execute-phase/steps/gap-closure-artifacts.md",
+  "msd-core/workflows/execute-phase/steps/gap-closure-uat-record.md",
   "msd-core/workflows/execute-phase/steps/partial-wave.md",
   "msd-core/workflows/execute-phase/steps/per-plan-executor-routing.md",
   "msd-core/workflows/execute-phase/steps/per-plan-worktree-gate.md",