feat: custom fields per project

Text, number, date or option-list fields defined in the project settings
(archived, never removed; their type is fixed once saved). Tickets hold
them, edited in the side panel, listed under the title and filtered by
option in the list view; also over GraphQL, REST (?field=ID:value) and MCP.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/domain/src/lib/project/project-settings.spec.ts

@@ -8,9 +8,12 @@ import { IssueStatusChangedEvent } from '../events/issue-status-changed.event';
 import { IssueFactory } from '../factories/issue.factory';
 import { ProjectFactory } from '../factories/project.factory';
 import { replay } from '../testing';
+import { Issue } from '../issue/issue';
 import { Project } from './project';
 import { ProjectRole } from './project-role';
+import { IssueUpdatedEvent } from '../events/issue-updated.event';
 import {
+  CustomFieldType,
   defaultProjectSettings,
   ProjectSettings,
   StatusCategory,
@@ -203,4 +206,151 @@ describe('Project settings', () => {
       ),
     ).toThrow(/Unknown ticket type/);
   });
+
+  describe('custom fields', () => {
+    const withFields = (): ProjectSettings => ({
+      ...defaultProjectSettings(),
+      customFields: [
+        {
+          id: 'browser',
+          name: ' Navegador ',
+          type: CustomFieldType.SELECT,
+          options: ['Chrome', ' Safari ', 'Chrome', ''],
+          archived: false,
+        },
+        {
+          id: 'COST',
+          name: 'Coste',
+          type: CustomFieldType.NUMBER,
+          options: ['ignored'],
+          archived: false,
+        },
+        {
+          id: 'GO_LIVE',
+          name: 'Salida',
+          type: CustomFieldType.DATE,
+          options: [],
+          archived: false,
+        },
+        {
+          id: 'CLIENT',
+          name: 'Cliente',
+          type: CustomFieldType.TEXT,
+          options: [],
+          archived: false,
+        },
+      ],
+    });
+
+    const newIssue = (project: Project) =>
+      new IssueFactory().create(
+        {
+          projectId: project.id,
+          projectKey: 'WEB',
+          number: 1,
+          title: 'Pago roto',
+          type: 'BUG',
+          reporterId: 'dev',
+          customFields: { BROWSER: 'Safari', COST: '1,5' },
+        },
+        project.workflow,
+      );
+
+    it('are normalised and kept; saving them unchanged is no change', () => {
+      const project = newProject();
+      project.updateSettings('owner', withFields());
+      expect(project.workflow.customFields[0]).toEqual({
+        id: 'BROWSER',
+        name: 'Navegador',
+        type: CustomFieldType.SELECT,
+        options: ['Chrome', 'Safari'],
+        archived: false,
+      });
+      expect(project.workflow.customFields[1].options).toEqual([]);
+
+      const before = project.getUncommittedEvents().length;
+      project.updateSettings('owner', structuredClone(project.settings));
+      // Clients that do not know about them leave them as they are.
+      const { customFields: _absent, ...older } = structuredClone(
+        project.settings,
+      );
+      project.updateSettings('owner', older);
+      expect(project.getUncommittedEvents()).toHaveLength(before);
+      expect(project.workflow.customFields).toHaveLength(4);
+    });
+
+    it('cannot be removed, change type or be a SELECT without options', () => {
+      const project = newProject();
+      project.updateSettings('owner', withFields());
+      const removed = { ...withFields(), customFields: [] };
+      expect(() => project.updateSettings('owner', removed)).toThrow(
+        /archívalo/i,
+      );
+      const retyped = withFields();
+      retyped.customFields![1].type = CustomFieldType.TEXT;
+      expect(() => project.updateSettings('owner', retyped)).toThrow(
+        /tipo no se puede cambiar/,
+      );
+      const empty = withFields();
+      empty.customFields![0].options = [' '];
+      expect(() => project.updateSettings('owner', empty)).toThrow(/opciones/);
+    });
+
+    it('check what a ticket holds, by type', () => {
+      const project = newProject();
+      project.updateSettings('owner', withFields());
+      const issue = newIssue(project);
+      expect(issue.customFields).toEqual({ BROWSER: 'Safari', COST: '1.5' });
+
+      const workflow = project.workflow;
+      const set = (customFields: Record<string, string | number | null>) =>
+        issue.updateDetails('dev', { customFields }, workflow);
+      expect(() => set({ BROWSER: 'Edge' })).toThrow(/no option/);
+      expect(() => set({ COST: 'mucho' })).toThrow(/number/);
+      expect(() => set({ GO_LIVE: '20/10/2026' })).toThrow(/date/);
+      expect(() => set({ CLIENT: 'x'.repeat(501) })).toThrow(/500/);
+      expect(() => set({ NOPE: 'x' })).toThrow(ValidationError);
+
+      set({ GO_LIVE: '2026-11-02', COST: 3, BROWSER: null });
+      const event = issue.getUncommittedEvents().at(-1) as IssueUpdatedEvent;
+      // The whole map, sorted: the projection just sets it.
+      expect(event.changes).toEqual({
+        customFields: { COST: '3', GO_LIVE: '2026-11-02' },
+      });
+      expect(Object.keys(event.changes.customFields!)).toEqual([
+        'COST',
+        'GO_LIVE',
+      ]);
+      // Same values again: nothing happens.
+      const count = issue.getUncommittedEvents().length;
+      set({ COST: '3' });
+      expect(issue.getUncommittedEvents()).toHaveLength(count);
+    });
+
+    it('archived ones can be cleared but not set', () => {
+      const project = newProject();
+      project.updateSettings('owner', withFields());
+      const issue = newIssue(project);
+      const archived = withFields();
+      archived.customFields![0].archived = true;
+      project.updateSettings('owner', archived);
+      expect(() =>
+        issue.updateDetails(
+          'dev',
+          { customFields: { BROWSER: 'Chrome' } },
+          project.workflow,
+        ),
+      ).toThrow(BusinessRuleError);
+      issue.updateDetails(
+        'dev',
+        { customFields: { BROWSER: '' } },
+        project.workflow,
+      );
+      expect(issue.customFields).toEqual({ COST: '1.5' });
+      // Replaying the events gives the same ticket.
+      expect(replay(issue, Issue).rebuilt.customFields).toEqual({
+        COST: '1.5',
+      });
+    });
+  });
 });