feat: templates per ticket type

Each ticket type can carry a starting description and a checklist, edited
in the project settings. New tickets of that type get the description
when they come without one and always get the checklist; the new ticket
form says what the template will add.

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

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

@@ -99,6 +99,29 @@ describe('Project settings', () => {
     );
   });
 
+  it('keeps a template per type, only when it says something', () => {
+    const project = newProject();
+    const settings = defaultProjectSettings();
+    settings.issueTypes[0].template = {
+      description: '  ## Pasos para reproducir  ',
+      checklist: [' Probar en Safari ', ''],
+    };
+    settings.issueTypes[1].template = { description: ' ', checklist: [] };
+    project.updateSettings('owner', settings);
+
+    expect(project.workflow.templateOf('BUG')).toEqual({
+      description: '## Pasos para reproducir',
+      checklist: ['Probar en Safari'],
+    });
+    expect(project.workflow.templateOf('FEATURE')).toBeNull();
+    const tooLong = defaultProjectSettings();
+    tooLong.issueTypes[0].template = {
+      description: null,
+      checklist: Array.from({ length: 21 }, (_, i) => `Paso ${i}`),
+    };
+    expect(() => project.updateSettings('owner', tooLong)).toThrow(/plantilla/);
+  });
+
   it('keeps work-in-progress limits, from 1 to 999', () => {
     const project = newProject();
     const limited = defaultProjectSettings();