fix(gemini): implement official hook contract

src/plugins/gemini-installation.ts

@@ -0,0 +1,63 @@
+import type { InstallConfig } from './base.js';
+import {
+  AGENT_KEY,
+  AUDIT_SCRIPT,
+  GUARD_SCRIPT,
+} from './gemini-contract.js';
+import type { RenderedGeminiDocument } from './gemini-config.js';
+import {
+  commitManagedInstallation,
+  preflightManagedInstallation,
+  prepareManagedInstallation,
+  type ManagedRuntimePaths,
+  type PreparedManagedInstallation,
+  type RenameFile,
+} from './managed-installation.js';
+
+const DISPLAY_NAME = 'Gemini CLI';
+const SETTINGS_DIRECTORY_LABEL = 'Gemini CLI configuration directory';
+const SETTINGS_LABEL = 'Gemini CLI user settings';
+
+export type GeminiRuntimePaths = ManagedRuntimePaths;
+export type PreparedGeminiInstallation = PreparedManagedInstallation;
+export type { RenameFile };
+
+export async function preflightGeminiInstallation(
+  config: InstallConfig,
+  settingsPath: string,
+): Promise<GeminiRuntimePaths> {
+  return preflightManagedInstallation({
+    agentKey: AGENT_KEY,
+    hookLocations: [{ directoryLabel: SETTINGS_DIRECTORY_LABEL, filePath: settingsPath }],
+    config,
+  }, GUARD_SCRIPT, AUDIT_SCRIPT);
+}
+
+export async function prepareGeminiInstallation(
+  config: InstallConfig,
+  rendered: RenderedGeminiDocument,
+): Promise<PreparedGeminiInstallation> {
+  const settingsSource = rendered.next ?? rendered.document.raw;
+  if (settingsSource === undefined) throw new Error('Gemini CLI hook settings are missing');
+  return prepareManagedInstallation({
+    agentKey: AGENT_KEY,
+    displayName: DISPLAY_NAME,
+    hookSources: [{
+      directoryLabel: SETTINGS_DIRECTORY_LABEL,
+      label: SETTINGS_LABEL,
+      filePath: rendered.document.filePath,
+      expectedSource: rendered.document.exists ? rendered.document.raw : undefined,
+      source: settingsSource,
+    }],
+    config,
+    guardOptions: { successOutput: '{}\n' },
+    auditOptions: { nativePayload: true, successOutput: '{}\n' },
+  }, GUARD_SCRIPT, AUDIT_SCRIPT);
+}
+
+export async function commitGeminiInstallation(
+  prepared: PreparedGeminiInstallation,
+  renameFile?: RenameFile,
+): Promise<void> {
+  await commitManagedInstallation(prepared, renameFile);
+}