feat: multi-tenant company refactor (GNU-19) (#153)

* feat: multi-tenant company refactor (GNU-19)

Introduce companies table, company_members, and user_preferences to
support multiple companies per user. All data scoping changes from
user_id to company_id across the entire codebase.

Key changes:
- Database migration: new tables, company_id on 40+ tables, backfill,
  RLS rewrite from user_id to company-member-based, updated RPCs
- Types: Company, CompanyMember, CompanyRole, UserPreferences types;
  company_id added to all entity interfaces; companyId on all events
- Engine: all 7 core functions take companyId; storno, period, year-end
  services updated; 16 report generators updated
- Middleware: company context resolution (cookie → prefs → first company)
- API routes: ~120 routes updated with requireCompanyId()
- Frontend: CompanyProvider context, layout/dashboard/onboarding updated
- Extensions: context factory, 9 extensions, all lib files updated
- Tests: 1880 tests passing, all helpers updated with company_id defaults

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add database migrations for multi-tenant company and team system (GNU-19)

Adds company_invitations, company creation RPC, team_members, account
deletion RPC, and teams table refactor migrations. Updates base
multi-tenant migration with cascading FKs and onboarding_step column.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add team types and update core infrastructure for multi-tenancy (GNU-19)

Adds TeamRole, MemberSource, and Team types. Refactors Supabase service
client to be stateless, updates middleware for team-aware routing, extends
CompanyContext with team/role fields, and updates extension service types
to accept companyId.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: thread company_id through business logic functions (GNU-19)

Replaces user_id scoping with company_id across all lib modules:
bookkeeping, documents, transactions, invoices, reconciliation, tax,
deadlines, and import. Updates corresponding tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: thread company_id through API routes and extensions (GNU-19)

Updates all existing API routes to extract and pass companyId. Updates
enable-banking and arcim-migration extensions for company-scoped
transaction ingestion and sync.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add company and team management API routes (GNU-19)

Adds CRUD endpoints for company members, company invitations, team
members, and team invitations. Includes invite token utilities, email
templates, and company switch server action.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add team/company UI components, pages, and dashboard updates (GNU-19)

Adds CompanySwitcher, ConsultantEmptyState, Step0RoleChoice, company
members and team management panels. Updates dashboard layout for
team-aware routing, onboarding for multi-step role choice, and auth
callback for team invite acceptance. Ignores supabase/.branches/.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: add null guards for company in import page (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: move appUrl declaration to outer scope in invite route (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: add optional chaining for company.name in members section (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: add optional chaining for second company.name in members section (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: add null guards for company in extension components (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: pass companyId to executeSIEImport in arcim-migration extension (GNU-19)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: update tests to use companyId instead of userId and improve type handling

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/auth/api-keys.ts

@@ -117,7 +117,7 @@ export function extractBearerToken(request: Request): string | null {
  */
 export async function validateApiKey(
   key: string
-): Promise<{ userId: string; scopes: ApiKeyScope[] } | { error: string; status: number }> {
+): Promise<{ userId: string; companyId: string; scopes: ApiKeyScope[] } | { error: string; status: number }> {
   if (!key.startsWith(KEY_PREFIX)) {
     return { error: 'Invalid API key format', status: 401 }
   }
@@ -141,6 +141,7 @@ export async function validateApiKey(
 
   return {
     userId: row.user_id,
+    companyId: row.company_id,
     scopes: validateScopes(row.scopes) ?? DEFAULT_SCOPES,
   }
 }

lib/auth/invite-tokens.ts

@@ -0,0 +1,31 @@
+import crypto from 'crypto'
+
+const INVITE_PREFIX = 'gnubok_inv_'
+const INVITE_TTL_DAYS = 7
+
+/**
+ * Generate an invite token and its SHA-256 hash.
+ * The raw token is sent via email; only the hash is stored in DB.
+ */
+export function generateInviteToken(): { token: string; hash: string } {
+  const raw = crypto.randomBytes(32).toString('base64url')
+  const token = `${INVITE_PREFIX}${raw}`
+  const hash = crypto.createHash('sha256').update(token).digest('hex')
+  return { token, hash }
+}
+
+/**
+ * Hash a raw invite token for lookup.
+ */
+export function hashInviteToken(token: string): string {
+  return crypto.createHash('sha256').update(token).digest('hex')
+}
+
+/**
+ * Get the expiration date for a new invite.
+ */
+export function getInviteExpiry(): Date {
+  const d = new Date()
+  d.setDate(d.getDate() + INVITE_TTL_DAYS)
+  return d
+}