Summary

Expands the fieldsets rule in dj-models from a single guideline to a three-band semantic pattern:

1. Untitled (None) fieldset — id + primary natural key only (e.g. email/slug). Identifiers always visible at top.
2. Named semantic sections — "Personal Info", "Details", "Role & Permissions", "Security", "Relations". Grouped by meaning, not DB column order.
3. "Important Dates" (always last, title case) — every datetime field lands here (created_at, updated_at, deleted_at, last_login, date_joined).

Also adds add_fieldsets guidance for creation forms (User primarily) — minimal required fields only.

Motivation

The current rule says "place identifiers and timestamps in the first fieldset." In practice, production codebases separate the two bands — identifiers in the untitled top fieldset, dates in a trailing "Important Dates" section. The split makes the top of the change view focused (just identity), the middle scannable (domain grouped by meaning), and keeps low-attention temporal fields out of the way.

The Django admin itself uses "Important dates" (lowercase d) on the default User admin. Standardizing on title case ("Important Dates") matches the other fieldset names in the skill's convention.

What changes

skills/dj-models/SKILL.md — replaces the single fieldsets bullet with:

• The three-band structure explained and exemplified
• A list of reusable section names (Personal Info / Details / Role & Permissions / Security / Relations)
• A new bullet for add_fieldsets on creatable models

Tradeoffs

• Title case "Important Dates" vs Django default "Important dates" — minor deviation. Worth it for consistency with the other title-cased section names.
• Rule could be tighter still (e.g., mandate exact section names) but leaving "Details" as a catchall lets teams name domain sections appropriately for their models.