sandbox phase 4 (UI): SIS console with revealed-density interactions

[William-Hill]

Parent: #116 · Spec: docs/superpowers/specs/2026-05-02-sis-pdp-ar-sandbox-design.md

Scope

• Route /sandbox/sis: two-pane record list + student detail (Demographics, Enrollments, Grades, Aid, Holds tabs).
• Banner-style density (~14 rows visible), monospace IDs and codes, slate (#2E3440) stage tint.
• Revealed-density: every abbreviated header, coded value (E/W/IP), and downstream-transformed cell expands on hover with plain English + "becomes →" preview.
• Filters: term, program, cohort. Sticky header.

Acceptance

• Record list renders 500+ synthetic students at interactive latency
• Every coded value has a hover gloss
• Cells whose values feed PDP transformations show a dotted underline + "becomes" preview
• Slate tint applied to page shell as 4px left border + breadcrumb chip

Estimate: 3–4 days. Depends on phase 1.