fix(atlas): repoint three catalog entries, and correct what they claim - #54

The report catalog names the test that evidences each requirement, so
renaming a test orphans its section. Three were left dangling:

  U5  test_active_flash_format_is_v20        -> missing
  U5b test_burned_versions_have_no_reader    -> missing
  U8  test_every_ladder_version_has_a_reader -> missing

They are not a mechanical rename, because all three encoded the same
false premise: that an unhandled storage version "falls out of the switch"
to a default. storage_fromFlash() has NO default case, deliberately, so
that -Werror=switch names any version nobody handled. An unlisted version
does not fall anywhere -- it fails the ARM build, which is what actually
happened on the passkeys branch.

  U5  -> test_last_shipped_never_moves_backwards. The role U5 described --
         "an independent witness for the number the whole gate turns on",
         because the static assert compares two constants in one header
         that one commit can raise together -- is now the LAST_SHIPPED
         ratchet. Its old title asserted V20, which is true on 7.16 and
         false on 7.15; the ratchet is true on both.
  U5b -> test_burned_versions_are_dispatched_to_the_wipe_path. The label
         must EXIST; what must not exist is a reader behind it.
  U8  -> test_every_shipped_version_has_a_reader. Scoped to SHIPPED on
         purpose: a burned format legitimately has none, so "every ladder
         version has a reader" would make burning one impossible to
         express. test_no_shipped_version_is_burned is what stops that
         scoping becoming a loophole.

Verified every catalog reference resolves to a test that exists -- 280
entries, all green -- rather than only the three I touched.