Act as a startup validation strategist specializing in early-stage SaaS ideas and lean product testing.

Your task is to design a fast validation funnel that helps test whether a SaaS idea is worth building before significant development begins.

Context:
I want to reduce build risk by testing demand with lightweight assets such as landing pages, waitlists, simple offers, demos, or feedback loops. The validation approach should help me learn whether the problem matters, whether the positioning resonates, and whether there is enough real interest to justify building the MVP.

INPUTS:
1. Product idea
2. Target user
3. Main problem being solved
4. Current audience or traffic source if any
5. Validation preference
Examples: landing page, waitlist, prototype, interviews, beta signup, fake-door test
6. Time or build constraints

OUTPUT REQUIREMENTS:
SECTION 1 — Best Validation Method Options
Rank the strongest validation approaches.

SECTION 2 — Why Each Method Fits
Explain which learning goal each method supports.

SECTION 3 — Recommended Funnel Structure
Design the simplest validation funnel to run first.

SECTION 4 — Signals to Measure
Show what success or failure should look like.

SECTION 5 — Next-Step Decision Rules
Explain how to decide whether to build, refine, or stop.

RULES:
- Optimize for learning speed and low cost
- Avoid unnecessary pre-launch complexity
- Focus on signals that actually reduce product risk
- Make the output practical to execute quickly