security: access control for particles (#169)

* setup firebase custom token

* docs

* docs

* feat: allow admin removing members from a network

* fix: properly handle fallback avatar and names

This is especially helpful in the case of members who were removed from
a network

js/src/lib/humans.ts

@@ -0,0 +1,43 @@
+import type { Human } from "@/api/types";
+import { getInitials } from "@/lib/utils";
+
+export const REMOVED_MEMBER_LABEL = "Removed member";
+export const REMOVED_MEMBER_INITIALS = "–";
+
+export interface HumanDisplay {
+  /** True when the human was found in the provided list. */
+  exists: boolean;
+  /** Short name for inline text (e.g. message sender). */
+  displayName: string;
+  /** Full email or fallback label for tooltips. */
+  email: string;
+  /** Initials for avatar fallback. */
+  initials: string;
+}
+
+/**
+ * Resolve a human's display info by id, falling back consistently when the
+ * human has been removed from the network. Member content (particles, reactions,
+ * etc.) is retained after removal, so every render path needs a graceful fallback
+ * instead of leaking raw ids into the UI.
+ */
+export function resolveHumanDisplay(
+  humanId: string | null | undefined,
+  humans: Human[] | undefined,
+): HumanDisplay {
+  const human = humanId ? humans?.find((h) => h.id === humanId) : undefined;
+  if (!human) {
+    return {
+      exists: false,
+      displayName: REMOVED_MEMBER_LABEL,
+      email: REMOVED_MEMBER_LABEL,
+      initials: REMOVED_MEMBER_INITIALS,
+    };
+  }
+  return {
+    exists: true,
+    displayName: human.email_prefix,
+    email: human.email,
+    initials: getInitials(human.email),
+  };
+}