fix(brand): inset _cyl's cream rim so no mark paints cream on transparent

_cyl stroked its cream rim centred on the top cap's ellipse, but that
ellipse's upper arc is the cylinder's silhouette — so half the 0.8-wide
stroke fell outside the gold. Invisible on cream, a stray white hairline
on dark. Shrink the rim's radii by half the stroke width so the whole
stroke lands inside the cap.

This was the last exemption in the cream-on-transparent guard: db-retry
and faststream-outbox were strict xfails. The guard now covers all 26
marks with no exemptions, and is renamed test_no_cream_on_transparent
since it is no longer scoped to the new marks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: lesnik512

architecture/brand-marks.md

@@ -25,10 +25,12 @@ renders on a transparent background, so `CREAM` is only ever a knockout painted
 ON TOP OF a `GOLD` shape, never standalone ink directly on the background:
 standalone cream is invisible on light surfaces (cream-on-cream) but shows as
 stray bright-white ink once the same `mark.svg` sits on a dark one, e.g.
-`lockup-dark.svg`'s README banner half. Enforced by
-`tests/test_projects.py::test_new_marks_have_no_cream_on_transparent`, which
-rasters every manifest repo's mark with its cream knockouts stripped and fails
-on any pixel that turns transparent instead of staying gold-backed. The two
+`lockup-dark.svg`'s README banner half. Enforced for **every** manifest repo, with
+no exemptions, by `tests/test_projects.py::test_no_cream_on_transparent`, which
+rasters each mark with its cream knockouts stripped and fails on any pixel that
+turns transparent instead of staying gold-backed. `_cyl`'s cream rim is inset by
+half its stroke width for exactly this reason — centred on the top cap's ellipse,
+half the stroke would have fallen outside the cylinder's silhouette. The two
 project templates reuse the org chevron. Two marks are built from a partner's
 literal logo path, recoloured: `modern-di-faststream` (FastStream's) and
 `modern-di-flask` (Flask's horn — the Flask Artwork License permits the logo

brand/build/symbols.py

@@ -23,12 +23,20 @@ def _cyl(
 ) -> str:
     """Database cylinder centred on (cx,cy)."""
     rx = 0.5 * r * w
+    ry = 0.16 * r
+    top = cy - h / 2 * r
+    # The top cap's upper arc IS the cylinder's silhouette, so a rim stroke
+    # centred on that ellipse would put half its width outside the gold —
+    # invisible on cream, but white ink on dark. Shrink the rim's radii by half
+    # the stroke width (plus a hair of margin) so the whole stroke lands inside.
+    rim_w = 0.8
+    inset = rim_w / 2 + 0.1
     return (
-        f'<ellipse cx="{cx}" cy="{cy - h / 2 * r:.1f}" rx="{rx:.1f}" ry="{0.16 * r:.1f}" fill="{fill}"/>'
-        f'<rect x="{cx - rx:.1f}" y="{cy - h / 2 * r:.1f}" width="{2 * rx:.1f}" height="{h * r:.1f}" fill="{fill}"/>'
-        f'<ellipse cx="{cx}" cy="{cy + h / 2 * r:.1f}" rx="{rx:.1f}" ry="{0.16 * r:.1f}" fill="{fill}"/>'
-        f'<ellipse cx="{cx}" cy="{cy - h / 2 * r:.1f}" rx="{rx:.1f}" ry="{0.16 * r:.1f}" '
-        f'fill="none" stroke="{CREAM}" stroke-width="0.8"/>'
+        f'<ellipse cx="{cx}" cy="{top:.1f}" rx="{rx:.1f}" ry="{ry:.1f}" fill="{fill}"/>'
+        f'<rect x="{cx - rx:.1f}" y="{top:.1f}" width="{2 * rx:.1f}" height="{h * r:.1f}" fill="{fill}"/>'
+        f'<ellipse cx="{cx}" cy="{cy + h / 2 * r:.1f}" rx="{rx:.1f}" ry="{ry:.1f}" fill="{fill}"/>'
+        f'<ellipse cx="{cx}" cy="{top:.1f}" rx="{rx - inset:.1f}" ry="{ry - inset:.1f}" '
+        f'fill="none" stroke="{CREAM}" stroke-width="{rim_w}"/>'
     )