chore(installer): drop unused fetchJson and fetchGitHubJson

Neither method has any callers. Also drop the corresponding test.

test/test-registry-client.js

@@ -163,19 +163,6 @@ async function testFetchGitHubYamlParsesCorrectly() {
   assert(result.modules[0].name === 'test', 'fetchGitHubYaml preserves YAML values');
 }
 
-async function testFetchGitHubJsonParsesCorrectly() {
-  const jsonContent = '{"name": "test", "version": "1.0.0"}';
-  const { client } = createStubbedClient({
-    apiResult: jsonContent,
-    rawResult: jsonContent,
-  });
-
-  const result = await client.fetchGitHubJson('owner', 'repo', 'file.json', 'main');
-
-  assert(result.name === 'test', 'fetchGitHubJson parses JSON correctly');
-  assert(result.version === '1.0.0', 'fetchGitHubJson preserves JSON values');
-}
-
 // ─── Runner ────────────────────────────────────────────────────────────────
 
 async function runTests() {
@@ -189,7 +176,6 @@ async function runTests() {
   await testUrlConstruction();
   await testRawUrlConstruction();
   await testFetchGitHubYamlParsesCorrectly();
-  await testFetchGitHubJsonParsesCorrectly();
 
   console.log(`\n${colors.cyan}========================================`);
   console.log('Test Results:');

tools/installer/modules/registry-client.js

@@ -55,17 +55,6 @@ class RegistryClient {
     return yaml.parse(content);
   }
 
-  /**
-   * Fetch a URL and parse the response as JSON.
-   * @param {string} url - URL to fetch
-   * @param {number} [timeout] - Timeout in ms
-   * @returns {Promise<Object>} Parsed JSON content
-   */
-  async fetchJson(url, timeout) {
-    const content = await this.fetch(url, timeout);
-    return JSON.parse(content);
-  }
-
   /**
    * Fetch a file from a GitHub repo using the Contents API first,
    * falling back to raw.githubusercontent.com if the API fails.
@@ -112,20 +101,6 @@ class RegistryClient {
     return yaml.parse(content);
   }
 
-  /**
-   * Fetch a file from GitHub and parse as JSON.
-   * @param {string} owner - Repository owner
-   * @param {string} repo  - Repository name
-   * @param {string} filePath - Path within the repo
-   * @param {string} ref   - Git ref
-   * @param {number} [timeout] - Timeout in ms
-   * @returns {Promise<Object>} Parsed JSON content
-   */
-  async fetchGitHubJson(owner, repo, filePath, ref, timeout) {
-    const content = await this.fetchGitHubFile(owner, repo, filePath, ref, timeout);
-    return JSON.parse(content);
-  }
-
   /**
    * Fetch a URL with custom headers. Used for GitHub API requests.
    * Follows up to 3 redirects.