feat: add use_commit_signing input with default false (#238)

* feat: add use_commit_signing input with default false

- Add new input 'use_commit_signing' to action.yml (defaults to false)
- Separate comment update functionality into standalone github-comment-server.ts
- Update MCP server configuration to conditionally load servers based on signing preference
- When commit signing is disabled, use specific Bash git commands (e.g., Bash(git add:*))
- When commit signing is enabled, use github-file-ops-server for atomic commits with signing
- Always include github-comment-server for comment updates regardless of signing mode
- Update prompt generation to provide appropriate instructions based on signing preference
- Add comprehensive test coverage for new functionality

This change simplifies the default setup for users who don't need commit signing,
while maintaining the option to enable it for those who require GitHub's commit
signature verification.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: auto-commit uncommitted changes when commit signing is disabled

- Check for uncommitted changes after Claude finishes (non-signing mode only)
- Automatically commit and push any uncommitted work to preserve Claude's changes
- Update tests to avoid actual git operations during test runs
- Pass use_commit_signing flag to branch cleanup logic

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/mcp/install-mcp-server.ts

@@ -67,28 +67,47 @@ export async function prepareMcpConfig(
     );
 
     const baseMcpConfig: { mcpServers: Record<string, unknown> } = {
-      mcpServers: {
-        github_file_ops: {
-          command: "bun",
-          args: [
-            "run",
-            `${process.env.GITHUB_ACTION_PATH}/src/mcp/github-file-ops-server.ts`,
-          ],
-          env: {
-            GITHUB_TOKEN: githubToken,
-            REPO_OWNER: owner,
-            REPO_NAME: repo,
-            BRANCH_NAME: branch,
-            REPO_DIR: process.env.GITHUB_WORKSPACE || process.cwd(),
-            ...(claudeCommentId && { CLAUDE_COMMENT_ID: claudeCommentId }),
-            GITHUB_EVENT_NAME: process.env.GITHUB_EVENT_NAME || "",
-            IS_PR: process.env.IS_PR || "false",
-            GITHUB_API_URL: GITHUB_API_URL,
-          },
-        },
+      mcpServers: {},
+    };
+
+    // Always include comment server for updating Claude comments
+    baseMcpConfig.mcpServers.github_comment = {
+      command: "bun",
+      args: [
+        "run",
+        `${process.env.GITHUB_ACTION_PATH}/src/mcp/github-comment-server.ts`,
+      ],
+      env: {
+        GITHUB_TOKEN: githubToken,
+        REPO_OWNER: owner,
+        REPO_NAME: repo,
+        ...(claudeCommentId && { CLAUDE_COMMENT_ID: claudeCommentId }),
+        GITHUB_EVENT_NAME: process.env.GITHUB_EVENT_NAME || "",
+        GITHUB_API_URL: GITHUB_API_URL,
       },
     };
 
+    // Include file ops server when commit signing is enabled
+    if (context.inputs.useCommitSigning) {
+      baseMcpConfig.mcpServers.github_file_ops = {
+        command: "bun",
+        args: [
+          "run",
+          `${process.env.GITHUB_ACTION_PATH}/src/mcp/github-file-ops-server.ts`,
+        ],
+        env: {
+          GITHUB_TOKEN: githubToken,
+          REPO_OWNER: owner,
+          REPO_NAME: repo,
+          BRANCH_NAME: branch,
+          REPO_DIR: process.env.GITHUB_WORKSPACE || process.cwd(),
+          GITHUB_EVENT_NAME: process.env.GITHUB_EVENT_NAME || "",
+          IS_PR: process.env.IS_PR || "false",
+          GITHUB_API_URL: GITHUB_API_URL,
+        },
+      };
+    }
+
     // Only add CI server if we have actions:read permission and we're in a PR context
     const hasActionsReadPermission =
       context.inputs.additionalPermissions.get("actions") === "read";