report: capture the shielded confirm screens, which nothing has ever shown

The RC run produced 1037 OLED frames. Not one matches pczt, orchard,
shielded or ironwood. Every catalogued Zcash PCZT test carries an empty
screenshot list, so the screenshot filter never selected any of them and no
shielded confirm screen has ever been rendered into the evidence.

That blind spot hid a real defect. The per-output shielded confirm builds
"Send shielded ZEC?\n<unified address>\nAmount: %s" for a three-row body,
and a real Orchard unified address is 106 characters -- three full rows on
its own, as the captured display-address frame shows. So the address tail
and the entire Amount line are never drawn. It is not a cosmetic screen
either: fsm_msg_zcash.h says total_amount is "a summary prompt" and that
Orchard output values "have their own verification gates", and this is that
gate. total_amount itself is taken straight from the host message.

Nothing looked wrong from outside, because the two Zcash flows that do get
captured both render correctly: the transparent output screen has a ~35
character t-address that fits, and display-address uses the paged
confirm_zcash_address path that handles all 106 characters.

Request frames on the one catalogued test that exercises a real shielded
output. This does not fix the rendering -- it makes the screen visible to
review, so the fix can be checked against a captured frame instead of an
assertion.

Verified: --screenshot-filter now selects the test, and the report still
renders 325 tests and passes --validate-junit against the RC artifacts.

Author: BitHighlander

scripts/generate-test-report.py

@@ -2038,8 +2038,14 @@ def _arg_shown(a):
           'test_private_send_preserves_compact_real_spend_order',
           'Private send preserves real-spend signature order',
           'Compact device signatures remain ordered by the real-spend actions when dummy actions '
-          'are interleaved.',
-          []),
+          'are interleaved. Screenshots requested because this is the only catalogued test that '
+          'renders the per-output shielded confirm, and that screen is the designed verification '
+          'gate for Orchard output values -- fsm_msg_zcash.h states outright that total_amount is '
+          'only a summary prompt and that output values "have their own verification gates". No '
+          'shielded frame has ever been captured: the RC run produced 1037 OLED frames and not '
+          'one matches pczt/orchard/shielded/ironwood, which is why a rendering defect on that '
+          'screen went unseen while the transparent path (short t-address, fits) looked correct.',
+          ['Shielded output confirm', 'Shielded transaction summary']),
          ('Z18', 'test_msg_zcash_sign_pczt',
           'test_missing_is_spend_is_rejected_before_device_call',
           'Missing spend classification rejected',