feat: describe organ functions in dashboard banners

[Jammy2211]

Summary

Replace grey “Board” / “Dashboard” masthead text with organ functions across all 15 shared dashboards. Broca reads “Assistants”, Heart reads “Tests”, and Broca follows Nerves in navigation. Logos, software names, taglines and CSS remain unchanged.

Refs #513. The task stays open until live publication has been verified.

API Changes

hero retains its signature and accepts legacy kind arguments; the displayed label now comes from shared organ metadata. Existing consumers adopt the change on regeneration.

Test Plan

• Compare all 15 hero outputs with the base version: only grey label text changes; SVG marks, taglines, metadata and CSS remain identical.
• Browser checks at 390, 768, 820, 1024 and 1440px: all labels fit.
• Full Brain suite: 1,252 passed in 376.83s, with checkout environment overrides removed to match CI. Tenant firewall: passed.
• Initial activated-environment run exposed an existing path-test isolation assumption (616 passed before failure); the isolated path tests and full CI-environment run pass without source changes.
• Regenerate and verify each published dashboard after merge.

Full API Changes

Changed Behaviour

• board._theme.hero: the grey label uses ORGANS[key]["function"] rather than the caller's legacy kind value. Unknown organs retain the Scientist fallback.
• board._theme.board_links: canonical navigation places Broca immediately after Nerves.

Migration

No caller edits needed; regenerate dashboards against updated Brain main.

Readiness

Heart YELLOW: generated-manifest drift and no rehearsal for current source. The human explicitly acknowledged the exact nine reasons and authorized shipping, merging and publication on 2026-10-08. No scientific library or workspace API changes; scientific workspace smoke is not applicable.