Lataa Numara 7.6.0

## What's New in v7.6.0

Numara 7.6.0 is a major release introducing **Cross-Page Imports**, **Full Offline PWA Support**, **Mobile Ergonomics**, calculation engine improvements, and security hardening.

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### Highlights

• **Cross-Page Variables & Imports**：You can now reference variables and calculations from any other page using `page("PageName")` (e.g. `r = page("Rates")`, then `r.hourly * 40`). Includes full autocomplete hinting and clickable page links in results!
• **Full Offline PWA & Service Worker**：Numara on the web can now be installed as a Progressive Web App (PWA) and launched completely offline from a cold start, with smart background cache updates.
• **Mobile Ergonomics & Notch Support**：Smooth full-screen experience on phones and tablets with safe-area insets (no overlapping home bars) and disabled auto-capitalization/autocorrect on math expressions.

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### Features & Improvements

#### Cross-Page Math & Navigation
• Reference other pages using `page("Name")` or `page("id")`.
• Auto-complete suggestions for imported page variables and object properties.
• Clickable page link tags in the results gutter to quickly navigate between related pages.

#### Progressive Web App & Offline
• **Service Worker**：Implemented network-first navigation with offline fallback and background asset revalidation.
• **Adaptive Icons**：Added dedicated Android maskable icons (`icon-maskable-192.png`, `icon-maskable-512.png`) with safe-zone margins and `apple-touch-icon.png` for iOS Home Screens.
• **PWA Enhancements**：Added app shortcuts (e.g. "New Calculation"), window controls overlay support, and device orientation flexibility.

#### Calculation Engine & Editor
• **Running Total Keyword Collisions**：Fixed an issue where variable names containing keywords (e.g. `total_amount = 500`) were excluded from running totals (`total`, `subtotal`).
• **Temporal Scope in Imports**：Cross-page expressions referencing `today` or `now` now resolve accurately in the importing page.
• **Live Search Panel**：Match positions and highlights now update in real-time as you edit text with the search panel open.
• **Bottom Answer Copying**：Fixed `Copy All Answers` and `Copy Page` when using the bottom answer position layout.
• **Formatting Crash Guards**：Added defensive fallbacks in number and currency formatting to prevent `RangeError` crashes when invalid precision settings are passed.

#### Security & Stability Hardening
• **Content Security Policy (CSP)**：Added strict CSP headers whitelisting only local assets and the Frankfurter currency API.
• **DOM XSS Protection**：Switched DOM updates across error dialogs, confirmations, plot titles, and status messages from `innerHTML` to `textContent`.
• **Sync Safety**：Cancelled pending debounced saves during page rename and deletion to eliminate race conditions in folder synchronization.
• **Electron Hardening**：Added window destruction guards and protocol restrictions (`http:`, `https:`) on external URL handlers.

#### CI/CD & Testing
• Automated multi-OS test matrix (Ubuntu, macOS, Windows) running **574 unit tests** on every push and pull request.

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### Contributors
Special thanks to @meghprkh for the contribution to the PWA Service Worker architecture and adaptive icons in PR #300!