Cut to kill the 0.4.0-alpha.15 aliasing: that string had denoted two different
code states (the crates.io publish vs an advanced, untagged git HEAD). This tag
pins the post-publish commits (75946cf WAC/git read-auth fix, f7785d7
payments::debit / R-04) under a single unambiguous version so all consumers
build identical code. Tags v0.4.0-alpha.12 through alpha.15 were never created.