standard: discussion + wiki templates + discussions-toggle policy (WS5/WS8)

[hyperpolymath]

Goal

Canonical DISCUSSION_TEMPLATE + wiki templates, and a decision on the discussions toggle.

Decide

• 136/375 repos have discussions OFF → enable estate-wide, or seed DISCUSSION_TEMPLATE only where on? (Templates can't seed where discussions are disabled.)

Do

• Canonical DISCUSSION_TEMPLATE set (ideas, q-and-a) — not reliably inherited, needs per-repo seeding (reposystem automation).
• Wiki templates: wikis are separate <repo>.wiki.git repos, no native templating → seed via automation.

Context

Plan WS5 + WS8.