Merge upstream LeanType v3.9.9 into dev

[AsafMah]

Goal

Merge the pinned LeanBitLab/LeanType v3.9.9 release (adb7c3755b0a9854d1f3cb8fe26bad033f93547e) into LeanTypeDual's dev branch without importing v4.0.0-beta commits.

Acceptance criteria

• Preserve LeanTypeDual identity, privacy flavors, and fork-only keyboard/toolbar/two-thumb features.
• Resolve and audit explicit plus Mergiraf automatic merge resolutions.
• Keep offline/offlinelite free of the Internet permission.
• Pass all four flavor compile gates.
• Match the origin/dev full-unit-test failure baseline; no additional failures.
• Reconcile draft release PR Release LeanTypeDual 3.11.0 #120 only after this integration is reviewable.

Status

• Integration branch and PR merge: sync LeanBitLab v3.9.9 #122 prepared
• Local flavor/test/manifest verification complete
• GitHub Actions run #29598368167 passed
• Review and merge merge: sync LeanBitLab v3.9.9 #122 into dev
• Reconcile draft release PR Release LeanTypeDual 3.11.0 #120 with updated dev