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.

lib/validations.ts

@@ -160,6 +160,14 @@ export const createSecretSchema = z.object({
   icon: z.string().max(10).optional().nullable(),
 })
 
+export const updateSecretSchema = z.object({
+  title: z.string().min(1).max(200).optional(),
+  value: z.string().min(1).max(5000).optional(),
+  description: z.string().max(500).optional().nullable(),
+  area: z.string().max(100).optional().nullable(),
+  icon: z.string().max(10).optional().nullable(),
+})
+
 // ─── Payments ────────────────────────────────────────────────────────────────
 
 export const logCashPaymentSchema = z.object({
@@ -363,6 +371,97 @@ export const updateAreaSchema = z.object({
   is_archived: z.boolean().optional(),
 })
 
+// ─── Forum, comments, tiers, roles, invites ──────────────────────────────────
+
+export const createForumThreadSchema = z.object({
+  title: z.string().min(1, 'Title is required').max(200),
+  body: z.string().max(20000).optional().nullable(),
+  category: z.string().min(1).max(50).optional(),
+})
+
+export const updateForumThreadSchema = z.object({
+  title: z.string().min(1).max(200).optional(),
+  body: z.string().max(20000).optional().nullable(),
+  category: z.string().min(1).max(50).optional(),
+  pinned: z.boolean().optional(),
+  locked: z.boolean().optional(),
+})
+
+export const commentEntityTypeSchema = z.enum(['forum_thread', 'proposal', 'incident', 'policy'])
+
+export const createCommentSchema = z.object({
+  entity_type: commentEntityTypeSchema,
+  entity_id: z.string().uuid('Invalid entity ID'),
+  body: z.string().min(1, 'Comment is required').max(10000),
+  parent_id: z.string().uuid().optional().nullable(),
+})
+
+export const updateCommentSchema = z.object({
+  body: z.string().min(1).max(10000),
+})
+
+export const createTierSchema = z.object({
+  slug: z.string().min(1).max(50).regex(/^[a-z0-9][a-z0-9_-]{0,49}$/, 'Slug must be lowercase letters, numbers, _ or -'),
+  name: z.string().min(1).max(100),
+  description: z.string().max(2000).optional().nullable(),
+  monthly_price_cents: z.number().int().min(0).max(100_000_000),
+  billing_cadence: z.enum(['monthly', 'quarterly', 'annual', 'one_time', 'custom']).default('monthly'),
+  sort_order: z.number().int().min(0).max(100000).optional(),
+})
+
+export const updateTierSchema = z.object({
+  name: z.string().min(1).max(100).optional(),
+  description: z.string().max(2000).optional().nullable(),
+  monthly_price_cents: z.number().int().min(0).max(100_000_000).optional(),
+  billing_cadence: z.enum(['monthly', 'quarterly', 'annual', 'one_time', 'custom']).optional(),
+  sort_order: z.number().int().min(0).max(100000).optional(),
+  is_archived: z.boolean().optional(),
+})
+
+export const upsertRoleLabelSchema = z.object({
+  role: z.enum(['admin', 'board', 'treasurer', 'member', 'associate']),
+  display_name: z.string().max(100).optional().nullable(),
+  description: z.string().max(500).optional().nullable(),
+  color: z.string().max(20).optional().nullable(),
+  sort_order: z.number().int().min(0).max(100000).optional(),
+})
+
+export const createCustomRoleSchema = z.object({
+  slug: z.string().min(1).max(50).regex(/^[a-z0-9][a-z0-9_-]{0,49}$/, 'Slug must be lowercase letters, numbers, _ or -'),
+  name: z.string().min(1).max(100),
+  description: z.string().max(500).optional().nullable(),
+  color: z.string().max(20).optional().nullable(),
+  sort_order: z.number().int().min(0).max(100000).optional(),
+})
+
+export const updateCustomRoleSchema = z.object({
+  name: z.string().min(1).max(100).optional(),
+  description: z.string().max(500).optional().nullable(),
+  color: z.string().max(20).optional().nullable(),
+  sort_order: z.number().int().min(0).max(100000).optional(),
+})
+
+export const createInviteSchema = z.object({
+  code: z.string().min(4).max(32).regex(/^[A-Z0-9-]+$/, 'Code must be uppercase letters, numbers, or hyphens').optional(),
+  label: z.string().max(100).optional().nullable(),
+  expires_at: flexibleDateTime(),
+  max_uses: z.number().int().min(1).max(100000).optional().nullable(),
+  is_enabled: z.boolean().optional(),
+})
+
+export const updateInviteSchema = z.object({
+  label: z.string().max(100).optional().nullable(),
+  expires_at: flexibleDateTime(),
+  max_uses: z.number().int().min(1).max(100000).optional().nullable(),
+  is_enabled: z.boolean().optional(),
+})
+
+export const createChannelSchema = z.object({
+  name: z.string().min(1).max(50).regex(/^[a-z0-9][a-z0-9-]{0,49}$/, 'Channel names must be lowercase letters, numbers, or hyphens'),
+  description: z.string().max(500).optional().nullable(),
+  channel_type: z.enum(['general', 'area', 'ops', 'project']).default('general'),
+})
+
 // ─── Generic ID schemas ──────────────────────────────────────────────────────
 
 export const uuidSchema = z.string().uuid('Invalid ID format')