fix(repo): use the viewed ref's editorconfig in file view, blame and editor (#39973)

The file view, blame and web editor read `.editorconfig` from the
default branch, so branch-specific settings like tab width were ignored.
The file view's middleware ran before the ref was resolved, and blame
never loaded it.

- `GetEditorconfig` reads the current commit, falling back to the
default branch only where no ref is resolved
- `Home` and `RefBlame` load the editorconfig after ref resolution

Fixes: https://github.com/go-gitea/gitea/issues/27413
Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: silverwind <me@silverwind.io>

tests/e2e/codeeditor.test.ts

@@ -1,16 +1,19 @@
 import {env} from 'node:process';
 import {expect, test} from '@playwright/test';
-import {login, apiCreateRepo, randomString} from './utils.ts';
+import {login, apiCreateFiles, apiCreateRepo, randomString} from './utils.ts';
 
 test('codeeditor textarea updates correctly', async ({page, request}) => {
   const repoName = `e2e-codeeditor-${randomString(8)}`;
-  await Promise.all([apiCreateRepo(request, {name: repoName}), login(page)]);
-  await page.goto(`/${env.GITEA_TEST_E2E_USER}/${repoName}/_new/main`);
-  await page.getByPlaceholder('Name your file…').fill('test.js');
-  await expect(page.locator('[data-tab="write"] .editor-loading')).toBeHidden();
-  const editor = page.locator('.cm-content[role="textbox"]');
-  await expect(editor).toBeVisible();
-  await editor.click();
-  await page.keyboard.type('const hello = "world";');
-  await expect(page.locator('textarea[name="content"]')).toHaveValue('const hello = "world";');
+  const owner = env.GITEA_TEST_E2E_USER;
+  await Promise.all([
+    (async () => {
+      await apiCreateRepo(request, {name: repoName});
+      await apiCreateFiles(request, owner, repoName, [{path: '.editorconfig', content: '[*]\nindent_size = 2\n'}], {newBranch: 'feature'});
+    })(),
+    login(page),
+  ]);
+  await page.goto(`/${owner}/${repoName}/_new/feature`);
+  await page.locator('.cm-content[role="textbox"]').click();
+  await page.keyboard.press('Tab');
+  await expect(page.locator('textarea[name="content"]')).toHaveValue('  ');
 });