[4.9.1] -- 2026-05-26

Plugin icon for the Codex marketplace display.

• Added assets/icon.svg (512x512, rounded-square tile with the tailtest shield + checkmark mark, emerald on near-black). Reads cleanly at marketplace tile sizes (32px, 64px, 128px).
• .codex-plugin/plugin.json now references the icon via interface.composerIcon = "./assets/icon.svg". Per the Codex plugin manifest spec; renders in the Codex app composer / marketplace browser.
• No behavioral changes. 400 tests still passing.

Triggered by tailtest-codex#5 (thanks to @internet-dot for the report and the concrete instructions).