LogTTY Build 19 fleet promotion

Promoted the exact canary-approved LogTTY 0.1.1 Build 19 candidate to rdmbair13m5 with rollback and independent post-install checks.

• Installed: /Applications/LogTTY.app, build 19, source commit b7abf60bd4a1abe0268e65b75230fe63f6586346.
• Archive SHA-256: f549d32cfcc6e8cd107100dc17e27eb058db2982dc8819c19f713a9b2348ad7c.
• Executable SHA-256: 957c1148893b2e990b573098a7e1aff367a50900787a167d1253cb0431961606.
• Verification: pinned host identity; GUI and install authority; universal strict-signed bundle; clean BuildInfo; one installed process; both existing databases ok; zero recent diagnostic reports and bounded error/fault records.
• Rollback: /Applications/LogTTY.app.rollback-build15-20260823T232438Z.
• Undo: quit LogTTY, preserve Build 19, restore the rollback path above to /Applications/LogTTY.app, and relaunch in the console session.
• Outstanding owner action: publish this changelog to the rdmbair13m5 Apple Notes folder from an Aqua Terminal session.