feat(calendar): enable calendar sync for Viktiga datum (#1853)

Turns on the calendar extension (built Feb 2026, stripped in the 2026-03-02 production readiness deploy, never re-enabled): ICS feed settings, calendar workspace, subscribe button on the Viktiga datum page.

Hardening before first real use: feed serve route now requires the creator to still be a company member (offboarding stops the feed); stable pagination (due_date + id, dedupe) on feed queries; fetches inside the logged try block; invoice events limited to sent/paid/partially_paid/overdue; event UIDs rebranded to accounted.se while zero feeds exist; APP_URL fallback fails closed in production; mobile stacking for the deadlines header; settings note that Google Calendar needs default notifications on subscribed calendars; calendar workspace aligned with the design system.

Skeptic reviewed (3 refutations, all fixed) plus one compliance swarm finding (fixed). No migrations.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/calendar/ics-generator.ts

@@ -20,7 +20,7 @@ export interface CalendarData {
  * Generate a stable UID for calendar events
  * This ensures updates to events are recognized by calendar apps
  */
-function getEventUID(type: string, id: string, domain: string = 'erp-base.se'): string {
+function getEventUID(type: string, id: string, domain: string = 'accounted.se'): string {
   return `${type}-${id}@${domain}`
 }
 

lib/extensions/_generated/enabled-extensions.ts

@@ -1,6 +1,7 @@
 // AUTO-GENERATED: do not edit. Run `npm run setup:extensions` to regenerate.
 
 export const ENABLED_EXTENSION_IDS: ReadonlySet<string> = new Set([
+  'calendar',
   'enable-banking',
   'email',
   'arcim-migration',

lib/extensions/_generated/extension-list.ts

@@ -1,5 +1,6 @@
 // AUTO-GENERATED: do not edit. Run `npm run setup:extensions` to regenerate.
 import type { Extension } from '../types'
+import { calendarExtension } from '@/extensions/general/calendar'
 import { enableBankingExtension } from '@/extensions/general/enable-banking'
 import { emailExtension } from '@/extensions/general/email'
 import { arcimMigrationExtension } from '@/extensions/general/arcim-migration'
@@ -16,6 +17,7 @@ import { shopifyExtension } from '@/extensions/general/shopify'
 import { mailExtension } from '@/extensions/general/mail'
 
 export const FIRST_PARTY_EXTENSIONS: Extension[] = [
+  calendarExtension,
   enableBankingExtension,
   emailExtension,
   arcimMigrationExtension,

lib/extensions/_generated/sector-definitions.ts

@@ -3,6 +3,21 @@ import type { ExtensionDefinition } from '../types'
 
 export const EXTENSION_DEFINITIONS: Record<string, ExtensionDefinition[]> = {
   'general': [
+    {
+          "slug": "calendar",
+          "name": "Kalender",
+          "sector": "general",
+          "category": "operations",
+          "icon": "Calendar",
+          "dataPattern": "core",
+          "description": "Fullständig kalendervy med månads-, vecko- och dagsvisning",
+          "longDescription": "Se alla fakturadatum och deadlines i en interaktiv kalender med månads-, vecko- och dagsvy.",
+          "readsCoreTables": [
+                "invoices",
+                "deadlines",
+                "customers"
+          ]
+    },
     {
           "slug": "enable-banking",
           "name": "Bankintegration (PSD2)",

lib/extensions/_generated/workspace-map.tsx

@@ -4,6 +4,7 @@ import type { ComponentType } from 'react'
 import type { WorkspaceComponentProps } from '../workspace-registry'
 
 export const WORKSPACES: Record<string, ComponentType<WorkspaceComponentProps>> = {
+  'general/calendar': dynamic(() => import('@/components/extensions/general/CalendarWorkspace')),
   'general/enable-banking': dynamic(() => import('@/components/extensions/general/EnableBankingWorkspace')),
   'general/arcim-migration': dynamic(() => import('@/components/extensions/general/ArcimMigrationWorkspace')),
   'general/tic': dynamic(() => import('@/components/extensions/general/TicWorkspace')),