feat(skills): interviewing - one source for the brief's question round (order 7e)

/trekbrief Phase 3 carried the interview form inline. It now asks for the
new skill voyage:interviewing by name (allowed-tools gains Skill) and keeps
only its own contract: the size class and budget, the three fixed questions
(framing first, class, storage), where each answer lands in the brief, and
the answers that decide nothing. Step 3a and the form points of Step 3c move
into the skill with their credits (Pocock, Osmani, Spec Kit; licences and
line ranges checked at the pinned commits).

Red baseline first (3 helper interviews against a fixed answer sheet,
Opus 5.5): 10-11 questions in round 1 (3 of 3), 15 of 31 without a
recommendation, a hollow answer written in as a decision (2 of 3), unasked
scope as a requirement (2 of 3). With the skill: 4, 0 of 12, 0 of 3, 0 of 3.
Fact questions and stopping did not fail without it.

Also: pointers to voyage:writing-criteria (S3) where criteria are asked and
written, both review skill names (S3 + S4) in the brief-reviewer prompt; the
intent pins that read moved text now read the skill, same assertions; the
Phase 7 line_ref moves with the shorter Phase 3; 7 eval cases (3/2/2).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

evals/skill-interviewing-fires-3/prompt.md

@@ -0,0 +1,10 @@
+---
+description: "Routing case: the interviewing skill should fire on this request (the reserve path outside the pipeline)."
+expected_outcome: "Claude calls the Skill tool for voyage:interviewing at least once."
+tags: [skill-trigger, skill=interviewing, from=baseline-ivw-hollow-answer]
+runs: 3
+max_turns: 4
+allowed_tools: [Read, Glob, Grep, Skill]
+---
+
+What I want from the reminder feature is still vague. Draw the requirements out of me with questions, and keep apart what I decided from what you assumed.