v0.11.6

Two new rules and one newly-reachable existing rule. A tag that validated
clean on 0.11.5 can report findings here: <Duration> is now format-checked
under <NonLinear>, and QR geometry without an image is reported. Catalog:
220 to 222.

Added

• VAST-4.4-qrcode-missing-image-url (warning). The mirror of
  -missing-scan-url for the other asset. Geometry tells the platform where to
  draw a QR code and how big; without <QrCodeImageUrl> there is nothing to
  draw. Like every rule in that group it comes from the guidance rather than the
  XSD, which requires none of the four QR children (they sit in an unbounded
  choice with minOccurs="0").
• VAST-3.0-adparameters-xmlencoded-value (warning). xmlEncoded is a boolean
  that nothing had ever looked at, so xmlEncoded="yes" validated clean. The
  player reads it to decide whether to XML decode the payload before handing it
  to VPAID or SIMID, and a value it cannot parse means it guesses. Accepts
  true, false, 1 and 0, case-insensitively.

Fixed

• <Duration> is format-checked under <NonLinear>. The CTV Ad Portfolio
  put a <Duration> there on 4.x, and the format rule had only ever been
  reached under <Linear> and, since 0.11.4, inside the extension container. No
  traversal was written for the NonLinear case and no fixture covered it, so
  nothing failed. Migrating the rule to element dispatch covered it without a
  line of code aimed at the case, which is the clearest evidence so far that the
  0.11.5 architecture does what it claims.

Changed

• <Icon>, <Tracking> and <Duration> migrated to element dispatch,
  removing the last of the duplicated element traversals. <Icon> had three
  call sites across two modules; <Tracking> had two.

  Two constraints surfaced doing it, both now explicit and tested. <Tracking>
  is genuinely position-dependent: <Verification> tracking uses its own
  vocabulary (verificationNotExecuted) and its own checker, so the Linear and
  NonLinear event enum must not be applied there. And the element gates had to
  become per element rather than per subtree, because <AdParameters> is valid
  under a VAST 2.0 <NonLinear> while the 4.x content model around it is not.

  Both were found by diffing the full fixture corpus rather than by the test
  suite, which is the argument for running that diff on every migration of this
  kind. Regression tests added for each.

  Rules whose subject really is a location keep their own traversals:
  VAST-2.0-nonlinear-resource, SIMID-1.0-simid-mediafile-required, the
  quartile-coverage warning, and the CTV Ad Portfolio container rules.