Automatic palette mode uses a misleading link icon #190

Context and request

src/zensical.toml labels the (prefers-color-scheme) palette entry as automatic mode but sets toggle.icon = "material/link". The link glyph does not communicate system-controlled light/dark behavior and was flagged when the canonical setting propagated to PSModule/Template-PSModule.

Material's automatic-brightness icon, material/brightness-auto, communicates the mode directly.

Acceptance criteria

• The automatic/system palette entry uses an icon that communicates automatic brightness, such as material/brightness-auto.
• Dark and light palette toggle icons remain coherent with the three-state cycle.
• The MSX documentation site builds successfully.
• Downstream documentation configurations derived from MSX are identified for a follow-up rollout.

Related work

• References 🪲 [Fix]: New modules inherit the current repository baseline PSModule/Template-PSModule#53