v1.2: add opt-in crash reporting foundation

[man612]

Summary

Adds privacy-first crash reporting without enabling remote uploads by default.

Local crash capture

• starts Electron Crashpad early in the main process
• keeps uploadToServer: false by default
• local minidumps can still be retained by Electron for crashes

Explicit consent

• adds a Share crash reports setting, default off
• upload can only become active when both:
  1. the release build has a valid HTTPS crash endpoint; and
  2. the user explicitly opts in
• disabling the setting immediately disables future uploads

Endpoint configuration

• release builds can receive the public endpoint through the repository variable WIREBOUND_CRASH_REPORT_URL
• builds without that variable show that remote reporting is unavailable
• non-HTTPS/invalid endpoints fail closed

Privacy

• no general analytics or behavioral tracking is added
• Wirebound adds no Android serials, terminal logs, DNS settings, or support-report contents to crash annotations
• Electron upload rate limiting is enabled
• adds docs/PRIVACY.md and links it from README

Important boundary

This makes Wirebound ready for real crash telemetry, but the repository does not currently contain or invent a crash-collector service. Remote reporting remains unavailable until the maintainer configures a compatible HTTPS Crashpad/Breakpad endpoint.