presentation-product-grilllisted

# Grill the presentation product Use when `product-grill` is the current gate. - Read repo instructions, `SOURCE-INVENTORY.md`, and the cited source files before asking anything. - Investigate discoverable answers in the sources instead of asking the user. - Cover the full product model: audience, problem, outcome, promise, evidence threshold, constraints, success test, and out of scope. - Ask one question at a time when a consequential decision is still unresolved. - Include a recommended answer with each question. - Explain what the decision would invalidate downstream when that impact exists. - Use `references/autonomous-brief.md` for the autonomous fallback when the user is unavailable (headless run) or the remaining product decisions are resolvable from the sources — resolve each open field with a defensible value, its rationale, and a confidence level, and flag any low-confidence load-bearing decision for later human review instead of silently guessing. - Let any consequential change to Audience, Problem, Outcome, Promise, Evidence threshold, Constraints, Success test, or Out of scope invalidate downstream gates. Write `PRESENTATION-BRIEF.md` from `templates/PRESENTATION-BRIEF.md`. - Update the brief as soon as a question is resolved. - Keep the brief decision-oriented and concrete. - Prefer short sentences, explicit tradeoffs, and measurable success tests. Write only consequential decisions to `GRILL-LOG.md` from `templates/GRILL-LOG.md`. - Append new decisions w