Add public agent profiles and community moderation

docs/DESIGN_SYSTEM.md

@@ -445,6 +445,62 @@ direct URL. Do not present authentication as a way around a disabled section.
   remain unique, ASCII-only credentials and must never appear on public-facing
   community surfaces. Authorized ISAC user operations may show both.
 
+### Public Agent profiles
+
+Public Agent profiles are community dossiers, not account-control screens. Lead
+with the shared `AgentIdentityLink` in its large state: circular portrait,
+display name, explicit `SHD.BUILD AGENT PROFILE` context, and a directional
+link cue. The profile owner may receive an `EDIT MY PROFILE` action in the
+header. Keep public content totals in a compact telemetry strip below the
+identity header, then place the field bio, public builds, published guides, and
+recent discussion in the primary column. Profile messages occupy the narrower
+communications column and may remain sticky where the viewport has room.
+
+Use `AgentIdentityLink` for author attribution on builds, guides, comments, and
+other community records. Its compact and default states combine the circular
+portrait, public display name, optional contextual metadata, and a clear link
+cue. Hover and focus-visible states may turn the name and cue orange. The
+portrait remains circular at every size; selectors may use square tactical
+thumbnails only where the avatar rules explicitly allow them.
+
+Public biographies and community comments use the shared `MarkdownEditor` and
+`MarkdownContent` pair. The editor supplies a small formatting toolbar,
+remaining-character count, concise help, a readable editorial typeface, and a
+minimum 44px touch target for toolbar actions on narrow screens. It supports
+headings, lists, quotes, links, emphasis, and inline code. Raw HTML is escaped.
+Only HTTP and HTTPS links are active; rendered links open separately with UGC,
+nofollow, and opener-isolation attributes. `MarkdownContent` must receive HTML
+from the server renderer, never raw user input or client-rendered Markdown.
+
+Rendered biography copy uses the editorial typeface and a restrained reading
+measure. Compact comment rendering uses the same hierarchy at a denser scale.
+Comment cards identify the author and date before the message. Activity cards
+identify the content type and title, render a useful excerpt, and provide a
+specific action such as `OPEN DISCUSSION`. Empty states state which public
+record is absent without implying an error.
+
+Profile visibility is an explicit public or hidden account setting. A hidden
+profile is excluded from public discovery and cannot receive new profile
+messages. Hiding it does not remove the Agent's display name or portrait from
+public builds, guides, or comments they authored. State this consequence beside
+the visibility control so the setting does not imply retroactive anonymity.
+
+Community forms use `PendingForm` to block duplicate submissions. Pending
+actions retain their label context, validation errors preserve entered text,
+and success or error feedback appears beside the affected form. All editor,
+link, and button controls require the shared orange focus-visible treatment.
+Message removal is a two-step, in-card confirmation: the first action reveals a
+red danger panel, then separate Cancel and Confirm Remove actions complete or
+abandon the request. Only an authorized author receives the removal control.
+
+Below 1000px, move profile communications beneath the primary content and stop
+using the sticky position. Below 650px, stack the identity header, telemetry,
+section headers, and content cards into one column. Expand owner actions,
+submission controls, and deletion controls to 44px touch targets. Keep the
+Cancel and Confirm Remove actions side by side when both labels fit. Respect
+`prefers-reduced-motion` without removing static hover, focus, pending, success,
+error, or danger indicators.
+
 ### Third-party identity buttons
 
 - Follow the identity provider's current official brand and sign-in guidelines.