fix(evals): cut path variance at its measured sources

- gstack-qa-evidence capture prints startedAt/completedAt/durationMs and, for
  --deadline captures, remainingMs; the functional report takes durations from
  them. The section clock notice asks for one clock read up front instead of one
  after every checkpoint (QA runs spent 7-14% of tool calls on date -u).
- ship plan-completion: skip the audit dispatch when discovery already found no
  plan (the dispatch-vs-skip conflict produced an optional 60-100 s subagent).
- materialize/checkpoint validation errors state the expected schema, so a
  rejected annotations file is fixable in one call instead of blocking the phase.
- session-runner counts turns from the transcript when a run times out, so
  timeouts stop reporting 'turn 0'.

test/fixtures/golden/codex-ship-SKILL.md

@@ -1556,9 +1556,9 @@ The child reads the plan and every referenced
 code file; the parent validates its report and applies the gates below.
 
 **Subagent prompt:** Substitute `<base>` and supply the active plan's absolute path
-or complete text, including relevant user-approved scope changes. If none exists,
-say so explicitly and let the child use the fallback search below. The child does
-not inherit the parent's conversation.
+or complete text, including user-approved scope changes. If none is known, say
+so; the child runs the fallback search below. If discovery found no plan, skip
+dispatch. The child does not inherit the parent's conversation.
 
 ````text
 You are running a ship-workflow plan completion audit. The base branch is `<base>`. Use `git diff origin/<base>` and inspect untracked files from `git status` to see the full proposed change. Do not commit or push. Report only: classify every item, but do not execute Gate Logic, ask the user, or advance the workflow. The parent applies those gates to your report.

test/fixtures/golden/factory-ship-SKILL.md

@@ -1536,9 +1536,9 @@ The child reads the plan and every referenced
 code file; the parent validates its report and applies the gates below.
 
 **Subagent prompt:** Substitute `<base>` and supply the active plan's absolute path
-or complete text, including relevant user-approved scope changes. If none exists,
-say so explicitly and let the child use the fallback search below. The child does
-not inherit the parent's conversation.
+or complete text, including user-approved scope changes. If none is known, say
+so; the child runs the fallback search below. If discovery found no plan, skip
+dispatch. The child does not inherit the parent's conversation.
 
 ````text
 You are running a ship-workflow plan completion audit. The base branch is `<base>`. Use `git diff origin/<base>` and inspect untracked files from `git status` to see the full proposed change. Do not commit or push. Report only: classify every item, but do not execute Gate Logic, ask the user, or advance the workflow. The parent applies those gates to your report.