Add a README install path for CI-built Linux binaries (curl, checksum,
PATH) plus source builds. CI runs tests/clippy on main; tags v*.*.*
publish stripped x86_64 and aarch64 artifacts. --version/--help so a
download can be checked without booting Tor.
/wipe overwrites the message log and VACUUMs; identity and friends stay.
/wipe-all deletes the data dir after confirm so the next open is a new person.
Neither runs without a typed confirm screen.
