Add opt-in capture mode for full-page screenshot stability

[Andrey1771]

Motivation

• Full-page/stitched screenshots show fixed/sticky overlays (notably .header-nav with backdrop-filter and blog stickies) duplicated or compositing-broken, while normal runtime UX must remain unchanged.
• Need a clean, opt-in technical mode that temporarily makes floating UI safe for sequential captures without spreading hacks across many components.

Description

• Added a centralized stylesheet tale-gameshop/src/styles/capture-mode.css that activates when html[data-capture-mode="true"] is set and disables animations, transitions and smooth scrolling, removes backdrop-filter effects and other compositing-sensitive properties, and converts selected floating elements to document flow.
• In capture mode .header-nav is temporarily rendered position: static (no permanent runtime change), the runtime spacer .main-page-down-header-padding is hidden, and visual appearance is preserved via a simple background/shadow fallback.
• Converted known problematic elements to capture-safe static behavior: .blog-toolbar-wrap, .blog-post-aside, .support-chat, .cookie-banner, .catalog-sidebar, .checkout-page-aside, .game-details-tabs, .account-sidebar and provided a generic hook data-capture-safe="disable-floating" for future overlays.
• Imported the new stylesheet in tale-gameshop/src/index.css and added a small dev helper tale-gameshop/src/utils/capture-mode.ts exposing enableCaptureMode() and disableCaptureMode() that set/remove the attribute on document.documentElement (the mode is opt-in and does not change normal runtime behavior unless enabled).

Testing

• Ran an automated CSS scan (python one-liner) to find position: fixed|sticky occurrences and used its output to choose selectors included in capture mode, and the scan completed successfully.
• Ran npm run lint in the app; the command failed in this environment due to missing tslint (sh: 1: tslint: not found), so lint could not be validated here.

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Codex Task