feat(KAN-34): rework blocker and ticket history

tests/Fixtures/ticket-detail-browser.mjs

@@ -101,6 +101,102 @@ try {
     }
     await page.setViewportSize({ width: 390, height: 1000 });
     await visit();
+    const blocker = content().locator('#ticket-blocker');
+    const blockerToggle = blocker.getByRole('checkbox', {
+        name: 'Mark ticket as blocked',
+        exact: true,
+    });
+    const blockerComment = blocker.getByLabel('Blocker comment', {
+        exact: true,
+    });
+    assert.equal(await blockerToggle.isChecked(), true);
+    assert.equal(
+        await blocker.getByText('Alex Morgan', { exact: true }).count(),
+        0,
+    );
+    assert.equal(
+        await content()
+            .locator('#ticket-history')
+            .getByText('Alex Morgan', { exact: true })
+            .count(),
+        1,
+    );
+    assert.equal(
+        await content()
+            .locator('#ticket-history')
+            .getByText('Status changed', { exact: true })
+            .count(),
+        1,
+    );
+    await blockerComment.fill('');
+    assert.equal(
+        await blockerComment.evaluate(
+            (element) => element.validity.valueMissing,
+        ),
+        true,
+    );
+    await blockerComment.fill('Waiting for a production decision.');
+    await blocker.getByRole('button', { name: 'Save blocker' }).click();
+    await page.getByText('Ticket updated.', { exact: true }).waitFor();
+    assert.equal(
+        await blockerComment.inputValue(),
+        'Waiting for a production decision.',
+    );
+    for (const label of ['Assignee', 'Reviewer']) {
+        const field = content()
+            .locator('#ticket-metadata dl > div')
+            .filter({ has: page.getByText(label, { exact: true }) });
+        assert.match(await field.locator('dd').innerText(), /Alex Morgan/);
+    }
+    await blockerToggle.uncheck();
+    await blocker.getByRole('button', { name: 'Unblock ticket' }).click();
+    await blocker
+        .getByText('This ticket currently has no active blocker.', {
+            exact: true,
+        })
+        .waitFor();
+    assert.equal(await blocker.getByLabel('Blocker comment').count(), 0);
+    await content().getByRole('button', { name: 'Change parent' }).click();
+    await page.waitForFunction(
+        () => document.activeElement?.id === 'parent_ticket_id',
+    );
+    const saveTicket = content().getByRole('button', {
+        name: 'Save changes',
+        exact: true,
+    });
+    assert.equal(
+        await content()
+            .getByRole('button', { name: 'Discard changes', exact: true })
+            .isDisabled(),
+        true,
+        'Saving the blocker must also update the ticket form defaults.',
+    );
+    await page
+        .getByLabel('Title', { exact: true })
+        .fill('Updated title after unblocking');
+    const ticketUpdate = page.waitForRequest(
+        (request) =>
+            request.method() === 'PATCH' &&
+            new URL(request.url()).pathname === '/projects/7/tickets/42',
+    );
+    await saveTicket.click();
+    const savedTicket = (await ticketUpdate).postDataJSON();
+    assert.equal(savedTicket.is_blocked, false);
+    assert.equal(savedTicket.blocked_comment, '');
+    assert.equal(Number(savedTicket.parent_ticket_id), 40);
+    assert.deepEqual(savedTicket.acceptance_criteria, [
+        { id: 10, text: 'Cache requests safely', checked: false, indent: 0 },
+        {
+            id: 11,
+            text: 'Invalidate when records change',
+            checked: false,
+            indent: 1,
+        },
+    ]);
+    await page
+        .getByRole('heading', { name: 'Updated title after unblocking' })
+        .waitFor();
+    await visit();
     await tabTo(edit());
     await page.keyboard.press('Enter');
     await page.getByLabel('Title', { exact: true }).fill('Unsaved title draft');

tests/Fixtures/ticket-detail.mjs

@@ -108,9 +108,18 @@ const ticket = {
         },
     ],
     worklog_entries: [
+        {
+            id: 2,
+            actor: null,
+            actor_id: null,
+            entry_type: 'status_changed',
+            summary: 'Moved from Backlog to Delivery / In progress.',
+            created_at: '2026-09-11T13:00:00Z',
+        },
         {
             id: 1,
             actor: user,
+            actor_id: user.id,
             entry_type: 'created',
             summary: 'Ticket created in the project backlog.',
             created_at: '2026-09-11T12:00:00Z',
@@ -395,7 +404,19 @@ if (serve) {
                 if (params.has('reject')) {
                     params.set('rejected', '1');
                 } else {
-                    savedForm = data;
+                    savedForm = {
+                        ...data,
+                        blocked_comment: data.is_blocked
+                            ? data.blocked_comment
+                            : null,
+                        field_values: data.field_values.map((fieldValue) => ({
+                            ...fieldValue,
+                            user_value:
+                                Number(fieldValue.value_user_id) === user.id
+                                    ? user
+                                    : null,
+                        })),
+                    };
                     params.set('saved', data.title);
                 }
             }
@@ -476,6 +497,9 @@ if (serve) {
             'feature/ENG-42-cache',
             'Cache implementation',
             'Ticket created in the project backlog.',
+            'Ticket created',
+            'Status changed',
+            'System',
         ]) {
             assert.ok(
                 html.includes(text),
@@ -486,6 +510,7 @@ if (serve) {
             'description',
             'checklist',
             'metadata',
+            'blocker',
             'relationships',
             'history',
             'git',