Merge upstream v1.12.26 - reconnect the fork to Element Web (management #0099)

The repo had no upstream ancestry: a whole tree arrived in one commit in May, so
every update meant re-applying our patches by hand onto a fresh checkout, and a file
Element moved would take our lines with it silently.

The real base was found by measuring tree distance across develop rather than trusting
the changelog: deadd548, not the v1.12.17 tag. With that set as a temporary graft, this
merge computed as a proper three-way merge - 32 conflicts instead of 1757.

Resolutions, each decided rather than defaulted:

- 24 GitHub workflows stay deleted; we build on GitLab CI.
- MImageBody.tsx is gone upstream, migrated to MVVM. Our ClamAV error label moved into
  ImageBodyViewModel.computeErrorLabel, ahead of the DecryptError branch, matching what
  VideoBodyViewModel and FileBodyViewModel already do.
- Upstream extracted the room list item body into RoomListItemContent. Our call
  participants list and its getInitials helper moved there; both sides' CSS classes and
  both sides' props are kept.
- matrix-js-sdk follows upstream at 42.2.0 - our git ref pin was a workaround for a
  stale ref, and following upstream is the point of this merge.
- Element Call stays ours. Checked before deciding: @element-hq/element-call-embedded
  is referenced nowhere in the tree, while webpack.config.ts needs
  @sorb/threadnet-call-embedded, so taking upstream's line would have deleted the noise
  suppression from #0054 without a word.

The lockfile was regenerated with pnpm 11.20.0, which upstream now requires through
devEngines. CI already runs corepack enable, and onFail: download makes it fetch that
version by itself.

Not yet accepted: this needs a build and the ClamAV functional test - send an encrypted
file, receive a rejected one - before it goes near main.

apps/web/playwright/sample-files/example-module.js

@@ -19,6 +19,7 @@ export default class ExampleModule {
     }
     async load() {
         const brand = this.api.config.get("brand");
+        // oxlint-disable-next-line no-alert
         alert(this.api.i18n.translate("key", { brand }));
     }
 }

apps/web/playwright/sample-files/index.ts

@@ -5,28 +5,25 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Com
 Please see LICENSE files in the repository root for full details.
 */
 
-import { dirname, join } from "node:path";
+import path from "node:path";
 import { fileURLToPath } from "node:url";
 import { readFile } from "node:fs/promises";
 import { readFileSync } from "node:fs";
 
-const __dirname = dirname(fileURLToPath(import.meta.url));
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 export function getSampleFilePath(file: string): string {
-    return join(__dirname, file);
+    return path.join(__dirname, file);
 }
 
-export function readSampleFile(file: string, encoding: null): Promise<NonSharedBuffer>;
+export function readSampleFile(file: string, encoding: null): Promise<Buffer>;
 export function readSampleFile(file: string, encoding?: BufferEncoding): Promise<string>;
-export function readSampleFile(
-    file: string,
-    encoding: BufferEncoding | null = "utf-8",
-): Promise<NonSharedBuffer | string> {
+export function readSampleFile(file: string, encoding: BufferEncoding | null = "utf-8"): Promise<Buffer | string> {
     return readFile(getSampleFilePath(file), encoding);
 }
 
-export function readSampleFileSync(file: string, encoding: null): NonSharedBuffer;
+export function readSampleFileSync(file: string, encoding: null): Buffer;
 export function readSampleFileSync(file: string, encoding?: BufferEncoding): string;
-export function readSampleFileSync(file: string, encoding: BufferEncoding | null = "utf-8"): NonSharedBuffer | string {
+export function readSampleFileSync(file: string, encoding: BufferEncoding | null = "utf-8"): Buffer | string {
     return readFileSync(getSampleFilePath(file), encoding);
 }

apps/web/playwright/sample-files/settings-module.js

@@ -0,0 +1,17 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+export default class SettingsModule {
+    static moduleApiVersion = "^*";
+    constructor(api) {
+        this.api = api;
+    }
+    async load() {
+        // oxlint-disable-next-line no-alert
+        alert(this.api.settings.getValue("language"));
+    }
+}

apps/web/playwright/sample-files/upload-module.js

@@ -0,0 +1,35 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+// Note: eslint-plugin-jsdoc doesn't like import types as parameters, so we
+// get around it with @typedef
+/**
+ * @typedef {import("@element-hq/element-web-module-api").Api} Api
+ */
+
+export default class CustomComponentModule {
+    static moduleApiVersion = "^*";
+    /**
+     * Basic module for testing.
+     * @param {Api} api API object
+     */
+    constructor(api) {
+        this.api = api;
+    }
+    async load() {
+        this.api.composer.addFileUploadOption({
+            type: "org.example.uploader",
+            label: "Example uploader",
+            onSelected: (_roomId, view) => {
+                this.api.composer.openFileUploadConfirmation(
+                    [new File(["test"], "testfile.txt", { type: "text/plain" })],
+                    view,
+                );
+            },
+        });
+    }
+}