feat: forum, polymorphic comments, custom tiers, multi-invite, secrets encryption

Big feature batch driven by the super-audit findings and the user's
follow-up requests.

Schema migration 021 (folded into schema.sql Section 13):
- forum_threads + polymorphic comments table keyed on (entity_type,
  entity_id). Entity types: forum_thread, proposal, incident, policy.
  Trigger maintains forum_threads.comment_count and last_comment_at.
- space_tiers per-space with monthly_price_cents, billing_cadence,
  is_system, sort_order. Trigger seeds plus/basic/associate on every
  space INSERT and backfills existing spaces. space_members.tier_id FK
  added and backfilled from the legacy enum value.
- space_role_labels (rename/recolor built-in roles per space).
  space_custom_roles + space_member_custom_roles for non-privileged
  extra labels. RLS gates by admin/board.
- space_invites: multi-code invites with expires_at, max_uses,
  uses_count, is_enabled. Legacy spaces.invite_code backfilled as a
  permanent enabled invite.
- secrets.encrypted_value bytea + encryption_version. Secrets RLS
  tightened. New comms_channels INSERT policy: any member can create;
  default channels are protected from deletion.
- knowledge_base.render_markdown boolean (default true).

Secrets encryption-at-rest:
- AES-256-GCM in lib/secrets/crypto.ts. Master key from
  SECRETS_ENCRYPTION_KEY env (64 hex chars).
- New revealSecret(id) server action: only path to plaintext, writes
  secret.revealed to activity_log.
- /ops/page.tsx no longer selects value or encrypted_value on the list
  endpoint - the original screenshot bug where ciphertext was already
  in the page bundle before "Reveal" is fixed.

UI:
- /forum index, /forum/new, /forum/[id]. Pin/lock/delete actions for
  admin/board.
- CommentThread component embedded on /proposals/[id], /incidents/[id],
  /policies/[slug]. Markdown rendering via react-markdown + remark-gfm.
- /comms sidebar: inline "+ New channel" form.
- /ops KB: row click opens markdown-rendering viewer modal.
- /settings: new Tiers tab and Invites tab. Inline price edit and
  archive/delete on tiers; copy/enable/disable/delete on invites.
- AtlasLogo replaces the terminal icon on the landing nav and footer.
  public/logo.svg wired as the favicon in app/layout.tsx metadata.
- Sidebar has a Forum nav link.

Server actions added:
- lib/actions/forum.ts, comms.ts, tiers.ts, roles.ts, invites.ts.
- lib/actions/secrets.ts rewritten with updateSecret + revealSecret.

Auth flow:
- joinSpace honors codes from space_invites first (enabled, expiry,
  use cap), falls back to legacy spaces.invite_code, increments
  uses_count on success.

Env:
- SECRETS_ENCRYPTION_KEY documented in .env.example and set on the
  Droplet's /opt/hackerspace-ops/.env.production.

README: live site link added (https://hackerspace.sh).

266/266 unit tests pass. Production build clean. Migration 021 will be
applied on the next deploy via /opt/hackerspace-ops/deploy.sh's
idempotent migration runner.

app/(app)/forum/[id]/page.tsx

@@ -0,0 +1,94 @@
+import Link from 'next/link'
+import { notFound } from 'next/navigation'
+import ReactMarkdown from 'react-markdown'
+import remarkGfm from 'remark-gfm'
+import { Pin, Lock } from 'lucide-react'
+import { createClient } from '@/lib/supabase/server'
+import { CommentThread } from '@/components/comments/comment-thread'
+import { loadComments } from '@/components/comments/load-comments'
+import { ThreadActions } from './thread-actions'
+
+export default async function ForumThreadPage({ params }: { params: Promise<{ id: string }> }) {
+  const { id } = await params
+  const supabase = await createClient()
+  const { data: { user } } = await supabase.auth.getUser()
+  if (!user) return null
+
+  const { data: self } = await supabase
+    .from('space_members')
+    .select('id, space_id, role, display_name')
+    .eq('user_id', user.id)
+    .in('status', ['current', 'unverified', 'late'])
+    .single()
+  if (!self) return null
+
+  const { data: thread } = await supabase
+    .from('forum_threads')
+    .select('id, title, body, category, pinned, locked, comment_count, created_at, author_id, space_id')
+    .eq('id', id)
+    .single()
+  if (!thread) notFound()
+  if (thread.space_id !== self.space_id) notFound()
+
+  let authorName = 'Member'
+  if (thread.author_id) {
+    const { data: a } = await supabase
+      .from('space_members')
+      .select('display_name')
+      .eq('id', thread.author_id)
+      .single()
+    if (a?.display_name) authorName = a.display_name
+  }
+
+  const comments = await loadComments(supabase, 'forum_thread', thread.id)
+  const isAuthor = self.id === thread.author_id
+  const canModerate = self.role === 'admin' || self.role === 'board'
+  const canEditThread = isAuthor || canModerate
+
+  return (
+    <div className="p-4 md:p-6 max-w-4xl space-y-5">
+      <div>
+        <Link href="/forum" className="font-mono text-[11px] tracking-widest text-muted-foreground hover:text-foreground uppercase">
+          ← Forum
+        </Link>
+      </div>
+
+      <header className="bg-card border border-border rounded p-5">
+        <div className="flex items-start justify-between gap-4 mb-2">
+          <div className="flex items-center gap-2 flex-wrap min-w-0">
+            {thread.pinned && <Pin className="w-4 h-4 text-amber-500 shrink-0" />}
+            {thread.locked && <Lock className="w-4 h-4 text-muted-foreground shrink-0" />}
+            <h1 className="font-sans text-xl font-semibold text-foreground">{thread.title}</h1>
+            <span className="font-mono text-[10px] px-1.5 py-0.5 rounded bg-muted text-muted-foreground uppercase tracking-widest">{thread.category}</span>
+          </div>
+          {canEditThread && (
+            <ThreadActions
+              threadId={thread.id}
+              pinned={thread.pinned}
+              locked={thread.locked}
+              canModerate={canModerate}
+              isAuthor={isAuthor}
+            />
+          )}
+        </div>
+        <p className="font-mono text-[11px] text-muted-foreground">
+          {authorName} · {new Date(thread.created_at).toLocaleString()}
+        </p>
+        {thread.body && (
+          <div className="prose prose-sm prose-neutral dark:prose-invert max-w-none mt-4 break-words">
+            <ReactMarkdown remarkPlugins={[remarkGfm]}>{thread.body}</ReactMarkdown>
+          </div>
+        )}
+      </header>
+
+      <CommentThread
+        entityType="forum_thread"
+        entityId={thread.id}
+        comments={comments}
+        currentMemberId={self.id}
+        canModerate={canModerate}
+        locked={thread.locked}
+      />
+    </div>
+  )
+}

app/(app)/forum/[id]/thread-actions.tsx

@@ -0,0 +1,72 @@
+'use client'
+
+import { useRouter } from 'next/navigation'
+import { toast } from 'sonner'
+import { Pin, Lock, Trash2 } from 'lucide-react'
+import { updateForumThread, deleteForumThread } from '@/lib/actions'
+
+interface Props {
+  threadId: string
+  pinned: boolean
+  locked: boolean
+  canModerate: boolean
+  isAuthor: boolean
+}
+
+export function ThreadActions({ threadId, pinned, locked, canModerate, isAuthor }: Props) {
+  const router = useRouter()
+
+  async function togglePinned() {
+    const result = await updateForumThread(threadId, { pinned: !pinned })
+    if (result.error) { toast.error(result.error); return }
+    router.refresh()
+  }
+
+  async function toggleLocked() {
+    const result = await updateForumThread(threadId, { locked: !locked })
+    if (result.error) { toast.error(result.error); return }
+    router.refresh()
+  }
+
+  async function handleDelete() {
+    if (!confirm('Delete this thread? All comments are deleted too.')) return
+    const result = await deleteForumThread(threadId)
+    if (result.error) { toast.error(result.error); return }
+    toast.success('Thread deleted')
+    router.push('/forum')
+  }
+
+  return (
+    <div className="flex items-center gap-1 shrink-0">
+      {canModerate && (
+        <>
+          <button
+            onClick={togglePinned}
+            className={`font-mono text-[10px] border border-border px-2 py-1 rounded transition flex items-center gap-1 ${pinned ? 'text-amber-600 bg-amber-50' : 'hover:border-amber-500 hover:text-amber-600'}`}
+            title={pinned ? 'Unpin' : 'Pin'}
+          >
+            <Pin className="w-3 h-3" />
+            {pinned ? 'Pinned' : 'Pin'}
+          </button>
+          <button
+            onClick={toggleLocked}
+            className={`font-mono text-[10px] border border-border px-2 py-1 rounded transition flex items-center gap-1 ${locked ? 'text-muted-foreground bg-muted' : 'hover:border-primary hover:text-primary'}`}
+            title={locked ? 'Unlock' : 'Lock'}
+          >
+            <Lock className="w-3 h-3" />
+            {locked ? 'Locked' : 'Lock'}
+          </button>
+        </>
+      )}
+      {(isAuthor || canModerate) && (
+        <button
+          onClick={handleDelete}
+          className="text-muted-foreground hover:text-red-500 transition p-1.5"
+          title="Delete"
+        >
+          <Trash2 className="w-3.5 h-3.5" />
+        </button>
+      )}
+    </div>
+  )
+}