Deterministic per-circle accent color (Signal/Matrix-style avatar
colors), derived from the circle id hash so it needs no storage of
its own - a small dot in the sidebar row and circle page header via
Pango markup, no CssProvider plumbing needed for a one-off color.
Invite now offers two buttons instead of one: read-only (the common
case) or read+write, turning a one-way share into a small
collaborative circle where invitees can post their own interpretations
back - same InterpOp::Author + share_interp_to_circle plumbing either
way, just a different Access level at invite time. No in-place
promotion yet: p2panda-auth's own add() errors with AlreadyAdded on an
existing member, so changing someone's level today means revoke then
re-invite (confirmed by reading the source, not assumed) - a real,
undocumented-until-now UX gap, not implemented in this pass.
Verified: full workspace build + test suite green, plus a second real
GUI smoke test confirming the accent dot renders correctly.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
