Remove webclient (extracted to Webatrice repo) (#6848)

The webclient has been extracted to https://github.com/seavor/Webatrice
and the Playwright e2e suite has moved to Sockatrice. Cockatrice keeps
no copy.

Deleted:
- webclient/ (entire tree, 349 files)
- .github/workflows/web-build.yml, web-lint.yml
- .husky/pre-commit (the only tracked husky hook; managed entirely
  from webclient's package.json which no longer exists)

Edited:
- .tx/config: dropped the webclient resource block; Webatrice/.tx/config
  now manages its own translations
- .github/workflows/translations-pull.yml: removed webclient locales
  from add-paths
- .github/workflows/desktop-build.yml, desktop-lint.yml: removed dead
  '!webclient/**' and '!.husky/**' path-filter exclusions
- .github/dependabot.yml: removed commented-out npm/webclient block
- Doxyfile: removed webclient/ from EXCLUDE list
- .ci/release_template.md: dropped Webatrice section (Webatrice now
  cuts its own releases)
- README.md: dropped 'first work on a webclient' line, added Webatrice
  to Related Repositories, updated translation paragraph and build
  badges

History preserved: every webclient commit remains recoverable via
git log on master before this commit.

webclient/prebuild.js

@@ -1,112 +0,0 @@
-const fse = require('fs-extra');
-const path = require('path');
-const util = require('util');
-const exec = util.promisify(require('child_process').exec);
-
-const ROOT_DIR = './src';
-const PUBLIC_DIR = './public';
-
-const protoFilesDir = `${PUBLIC_DIR}/pb`;
-const i18nDefaultFile = `${ROOT_DIR}/i18n-default.json`;
-const serverPropsFile = `${ROOT_DIR}/server-props.json`;
-const masterProtoFile = `${ROOT_DIR}/proto-files.json`;
-
-const sharedFiles = [
-  ['../libcockatrice_protocol/libcockatrice/protocol/pb', protoFilesDir],
-  ['../cockatrice/resources/countries', `${ROOT_DIR}/images/countries`],
-];
-
-const i18nFileRegex = /\.i18n\.json$/;
-
-const i18nOnly = process.argv.indexOf('-i18nOnly') > -1;
-
-(async () => {
-  if (i18nOnly) {
-    await createI18NDefault();
-    return;
-  }
-
-  // make sure these files finish copying before master file is created
-  await copySharedFiles();
-
-  await createMasterProtoFile();
-  await createServerProps();
-  await createI18NDefault();
-})();
-
-async function copySharedFiles() {
-  try {
-    return await Promise.all(sharedFiles.map(([src, dest]) => fse.copy(src, dest, { overwrite: true })));
-  } catch (e) {
-    console.error(e);
-    process.exitCode = 1;
-  }
-}
-
-async function createMasterProtoFile() {
-  try {
-    fse.readdir(protoFilesDir, (err, files) => {
-      if (err) throw err;
-
-      fse.outputFile(masterProtoFile, JSON.stringify(files.filter(file => /\.proto$/.test(file))));
-    });
-  } catch (e) {
-    console.error(e);
-    process.exitCode = 1;
-  }
-}
-
-async function createServerProps() {
-  try {
-    fse.outputFile(serverPropsFile, JSON.stringify({
-      REACT_APP_VERSION: await getCommitHash(),
-    }));
-  } catch (e) {
-    console.error(e);
-    process.exitCode = 1;
-  }
-}
-
-async function createI18NDefault() {
-  try {
-    const files = getAllFiles(ROOT_DIR, i18nFileRegex);
-    const allJson = await Promise.all(files.map(file => fse.readJson(file)));
-
-    const rollup = allJson.reduce((acc, json) => {
-      const newKeys = Object.keys(json);
-
-      newKeys.forEach(key => {
-        if (acc[key]) {
-          throw new Error(`i18n key collision: ${key}\n${JSON.stringify(json)}`);
-        }
-
-        acc[key] = json[key];
-      });
-
-      return acc;
-    }, {});
-
-    fse.outputFile(i18nDefaultFile, JSON.stringify(rollup, null, 2));
-  } catch (e) {
-    console.error(e);
-    process.exitCode = 1;
-  }
-}
-
-async function getCommitHash() {
-  return (await exec('git rev-parse HEAD')).stdout.trim();
-}
-
-function getAllFiles(dirPath, regex = /./, allFiles = []) {
-  return fse.readdirSync(dirPath).reduce((files, file) => {
-    const filePath = dirPath + "/" + file;
-
-    if (fse.statSync(filePath).isDirectory()) {
-      files.concat(getAllFiles(filePath, regex, files));
-    } else if (regex.test(file)) {
-      files.push(path.join(__dirname, filePath));
-    }
-
-    return files;
-  }, allFiles);
-}