A blocked launcher preflight only said to update the launcher, so a user
whose PATH resolved an old npm/nvm `t3` kept running `t3 service update`,
which reinstalled that same stale CLI and reported success.

The preflight reason now names the offered and required launcher
protocols, the exact-version installer command, `t3 --version` and
`which -a t3` to spot a shadowed CLI, and the installer's default
`~/.local/bin/t3 service install`. It also says a desktop app update
does not update the CLI. `t3 service install`/`update` no-op lines now
name the CLI entry script or executable that ran.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>