Enable NASbook V07 automatic updates

[sufyanaser]

What changed

• upgrades NASbook metadata and installer naming to V07 / 7.0.0
• adds the official electron-updater client for packaged Windows builds
• checks GitHub automatically after startup and every six hours
• downloads stable updates in the background and installs them on normal application exit
• keeps the existing appId and local data location
• publishes latest.yml and the NSIS blockmap beside the installer
• includes the live heading-collapse stability fix from develop
• makes collapse chevrons prominent and state-correct: down when open, toward text when closed in RTL/LTR

Update bootstrap limitation

V07 is the first build containing the update client. Existing V06 installations must install V07 once over the current installation. Every release after V07 can then arrive and install automatically.

Validation

• lint: passed with zero warnings
• TypeScript: passed
• tests: 64/64 passed
• production build: passed
• Electron native runtime smoke: passed
• npm audit: 0 vulnerabilities
• packaged V07 runtime: passed
• latest.yml path and SHA-512 match the generated installer
• collapse open/closed runtime state: passed; heading top stayed 319.5px
• design QA: passed