Add configurable timeout and retry for git network operations

Add per-attempt timeout (default 300s) and Kubernetes probe-style retry
configuration for git fetch, lfs-fetch, and ls-remote. New action inputs:
timeout, retry-max-attempts, retry-min-backoff, retry-max-backoff.

Fixes https://github.com/actions/checkout/issues/631

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/git-source-settings.ts

@@ -118,4 +118,27 @@ export interface IGitSourceSettings {
    * User override on the GitHub Server/Host URL that hosts the repository to be cloned
    */
   githubServerUrl: string | undefined
+
+  /**
+   * Timeout in seconds for each network git operation attempt (fetch, lfs-fetch, ls-remote).
+   * 0 means no timeout. Similar to Kubernetes probe timeoutSeconds.
+   */
+  timeout: number
+
+  /**
+   * Maximum number of retry attempts for failed network git operations.
+   * Similar to Kubernetes probe failureThreshold.
+   */
+  retryMaxAttempts: number
+
+  /**
+   * Minimum backoff time in seconds between retry attempts.
+   * Similar to Kubernetes probe periodSeconds.
+   */
+  retryMinBackoff: number
+
+  /**
+   * Maximum backoff time in seconds between retry attempts.
+   */
+  retryMaxBackoff: number
 }