feat: rebrand QuestboardAI -> TaskFlow everywhere (UI, locales, index.html)

fix: canvas limit alert+redirect, prices match landing (/), default manual sketch mode

fix: subscription page - replace outdated content with real comparison table, fix gap layout

fix: sidebar gap layout bug, add active daily AI count display

Implement paywall modal, subscription pages, and translation keys

feat: rebrand PlotTwist to QuestboardAI

feat: rebrand TaskFlow to PlotTwist and align with Human-in-the-Loop AI Agent Proof-of-Work vision

init