Release LeanTypeDual 0.1.0

[AsafMah]

Summary

• Restart LeanTypeDual's visible version series at 0.1.0 while retaining Android versionCode 4100. The CI signer exactly matches the installed non-debug 3.9.1/3910 package, so the signed artifacts remain upgrade-compatible. The separate com.asafmah.leantypedual application ID remains the actual collision boundary from upstream LeanType.
• Include the pinned LeanBitLab v4.0.2 integrations from merge: sync LeanBitLab v3.9.9 #122 and merge: stack LeanBitLab v4.0.2 #124, while preserving LeanTypeDual's Java fallback gesture engine, privacy flavors, two-thumb behavior, and fork-owned release metadata.
• Keep ordinary lowercase words such as to, no, and meet lowercase for taps and swipes without Shift.
• Consolidate release publishing onto one fail-fast signing workflow that builds and verifies all four signed APK flavors; Gradle now refuses to package unsigned release artifacts.

Refs #119. Supersedes closed draft #120 after the release branch was renamed from chore/release-3.11.0.

Verification completed

• All four flavor compile gates pass after v4.0.2 reconciliation.
• Focused IME, suggestion, Java-fallback, dictionary, AppUpgrade, settings, capitalization, Unicode, immediate-autospace, and combining-mode regressions pass.
• Full Offline debug baseline: release branch 313 tests / 10 known failures / 1 skipped versus current dev 309 tests / the same 10 failures / 1 skipped.
• Offline runTests: 313 tests / the same four Windows parser failures / 1 skipped; Linux CI on the reconciled pre-reset commit passed.
• Standard Full debug APK reports 0.1.0, code 4100, package com.asafmah.leantypedual.debug.
• Phone upgrade proof: adb install -r upgraded the non-debug package from 3.9.1/3910 to the CI-signed Standard Full 0.1.0/4100 APK; the installed signer still matches, both production and debug settings activities launch without a crash, and the active debug IME remained selected.
• python -m unittest tools.test_release passes and the release-note generator resolves release_notes_v0.1.0.md.
• Local unsigned release packaging now fails explicitly instead of emitting installable-looking unsigned APKs.
• Per-flavor low-API signing coverage is enforced in CI: Standard and Standard Full (minSdk 23) plus Offline Lite (minSdk 21) verify v1/JAR signatures across API 21–23; Offline has minSdk 26 and verifies v2/v3 for its supported devices. Final unit run #30220601580 and release run #30220604785 both pass.

Signing verification

Final Release workflow run #30220604785 built and verified all four signed flavors, including explicit API 21–23 v1/JAR coverage for every compatible flavor. Every APK uses one RSA signer (CN=AsafMah) with certificate SHA-256 c032eafcd7ce9197fd9e636f2c86b1590f0a84f8f73016c66d63c1382af81554. That fingerprint exactly matches the installed non-debug LeanTypeDual 3.9.1 package and each published v3.9.1 package population (com.asafmah.leantypedual, .offline, and .offlinelite); an in-place signed base-package upgrade to 0.1.0 succeeded. Local release packaging without real credentials now fails instead of producing unsigned APKs.

Remaining release gates

• Complete behavioral phone smoke in a real editor: typing, direct IME switching, custom-layout restoration, and lowercase tap/swipe casing.
• Install the signed release candidate on the tablet and verify upgrade/data retention plus the same behavioral smoke.
• Mark this PR ready only after the remaining phone and tablet behavioral smoke gates pass.

No tag or production release should be created from this draft yet.