feat(trappist-1): draw the habitable zone as a dataset of the system

[alowpoly]

Change

TRAPPIST-1's star gains a dataset of its whole system, "Habitable zone": a green band in the plane of the planets' orbits, listed on the system's card (README).

• New package kind, plane-bank: one prepared picture on a plane around its host, drawn while a dataset shows it.
• "Off" on system cards: a star's own opening dataset is listed as "Off" there, so one entry is always selected. ε Eridani's card gains it too.
• Includes fix(trappist-1): pin the world files that carry b's and e's orbit colors #1528's pin commit.

Sources and processing

• Source: the Habitable Zone Gallery's JSON product (Kane & Gelino 2012); seven rows kept.
• Processing: four distances drawn as flat rings on the orbits' mean plane.
• Meaning and limits: calculated (Kopparapu et al. 2013, 2014), not observed; the star is 34 K below the model's range.

Prepared assets

• Baked the zone and the star (images reused).
• Published trappist-1-habitable-zone and trappist-1.
• Committed both inventories, no baked files.

Evidence and limits

Proves the change: headless on a local dev server, the system page opens on "Off" with no plane mounted. Selected, the plane is whole at 42 million km and gone within 8 million km of the star.

Clean: affected tests; objects, bake, renderer and site typechecks; ESLint; source checks.

Limits: not tested on an iPad. A phone's picker still names "Off" as "Color".

PR rules: titles, PDS4 provenance and ISO plain language.