feat(cta): hero CTA modal + doc page enrichment

[fefsgfswewse-star]

Summary

• New CTA modal experience: HeroButton primary CTA, vertical stepper (StepCard + StepperConnector), AuroraBacklight atmosphere, LaunchedChip, SectionDivider, clipboard install flow with Win+R/Ctrl+V/Enter keystrokes.
• Doc page enrichment across 17 marketing/doc routes via new DocBlocks building blocks (DocFeatureGrid, DocStat, DocSectionLabel) — partners, support, what-is-my-ip, security-model, vpn-servers, streaming, business, blog, sign-in, download, etc.
• Theme + small fixes: dark OLED emerald reset on blog/sign-in/download, sign-in submit button type, escaped JSX quotes on vpn-servers, stable keys in DocFeatureGrid.

Why

CTA flow was visually flat and the doc pages were thin walls of text. This pass rebuilds the primary conversion modal as a guided stepper with atmosphere, and gives every doc/marketing route a consistent visual rhythm via shared DocBlocks.

Notable files

• src/components/ui/CtaModal.tsx (+949) — new modal shell, HeroButton, StepCard cascade, AuroraBacklight, clipboard flow.
• src/components/proton/DocBlocks.tsx (+147) — DocFeatureGrid / DocStat / DocSectionLabel.
• 17 page files under src/app/(site)/... updated to use DocBlocks.

Test plan

• npm run check (lint + typecheck + build) passes
• Visual check of CTA modal: hero button always clickable, stepper cascade, aurora backlight inside modal shell
• Visual check of enriched doc pages on desktop + mobile
• No Russian strings in src/ (UI/comments/labels)