100-question progress counter & 85-question warning banner

[SanAlexis]

Context

v8 progression model requires two UI signals during the trial period:

1. 0–84 questions: Progress counter visible in dashboard/session UI: "47 / 100 — unlock partner discovery at 100"
2. 85–99 questions: Warning banner: "N questions remaining — subscribe to unlock partner discovery"
3. At question 85, send an email nudge via Resend encouraging subscription

Acceptance criteria

• Progress counter displayed prominently (dashboard + session UI)
• Warning banner appears at 85 questions — more urgent visual treatment
• Email nudge sent at question 85 via Resend
• Counter updates in real-time as questions are answered
• Depends on questions_answered column from Rework: Four-state user tier model (trial/locked/active/dormant) #64 (tier model rework)