fix: ship token launch polish and hardening follow-ups

[nullxnothing]

Summary

This lands the current refactor/token-launch-ux branch on top of main and folds in the remaining hardening and production stability follow-ups.

Included

• ship the current token-launch UX polish already on this branch
• harden browser navigation against localhost, private-network, internal-domain, credentialed, and non-HTTP(S) targets
• validate and throttle email:send at the IPC boundary
• stabilize the Image Editor readiness handshake so miniPaint cannot get stuck in a permanent loading state
• add BrowserService coverage and extend smoke coverage to exercise the packaged Image Editor flow
• reconcile app version metadata to 2.0.11
• keep the tightened production CSP while explicitly allowing the static miniPaint bootstrap script by hash

Verification

• pnpm run typecheck
• pnpm run test
• pnpm run test:smoke

GitHub

Closes #43
Closes #45
Closes #46
Closes #50

Supersedes #49.