fix(qa): define evidence.json where it is built, point the preparation gate at the next section, name measured command durations in the report template

Recurring qa/qa-only workflow-judge complaints in CI (clarity/actionability 3.33).

qa-only/SKILL.md.tmpl

@@ -71,7 +71,7 @@ If neither exists, use git diff analysis.
 
 ## Select Surfaces and Isolation
 
-Load the shared preparation gate now: complete its scope and selected-method Reads,
+Load the shared preparation gate now (next section): complete its scope and selected-method Reads,
 await their results, and select the surfaces. Defer charters, clocks and probes to
 Run the Selected Checks, after report ownership and conditional browser setup below.