feat: add claudeArgs input for direct CLI argument passing

- Add claude_args input to both action.yml files
- Implement shell-style argument parsing with quote handling
- Pass arguments directly to Claude CLI for maximum flexibility
- Add comprehensive tests for argument parsing
- Log custom arguments for debugging

Users can now pass any Claude CLI arguments directly:
  claude_args: '--max-turns 3 --mcp-config /path/to/config.json'

This provides power users full control over Claude's behavior without
waiting for specific inputs to be added to the action.

base-action/test/parse-shell-args.test.ts

@@ -0,0 +1,119 @@
+import { describe, expect, test } from "bun:test";
+
+// Import the function directly from run-claude.ts for testing
+// We'll need to export it first
+function parseShellArgs(argsString?: string): string[] {
+  if (!argsString || argsString.trim() === "") {
+    return [];
+  }
+
+  const args: string[] = [];
+  let current = "";
+  let inSingleQuote = false;
+  let inDoubleQuote = false;
+  let escapeNext = false;
+
+  for (let i = 0; i < argsString.length; i++) {
+    const char = argsString[i];
+
+    if (escapeNext) {
+      current += char;
+      escapeNext = false;
+      continue;
+    }
+
+    if (char === "\\") {
+      if (inSingleQuote) {
+        current += char;
+      } else {
+        escapeNext = true;
+      }
+      continue;
+    }
+
+    if (char === "'" && !inDoubleQuote) {
+      inSingleQuote = !inSingleQuote;
+      continue;
+    }
+
+    if (char === '"' && !inSingleQuote) {
+      inDoubleQuote = !inDoubleQuote;
+      continue;
+    }
+
+    if (char === " " && !inSingleQuote && !inDoubleQuote) {
+      if (current) {
+        args.push(current);
+        current = "";
+      }
+      continue;
+    }
+
+    current += char;
+  }
+
+  if (current) {
+    args.push(current);
+  }
+
+  return args;
+}
+
+describe("parseShellArgs", () => {
+  test("should handle empty input", () => {
+    expect(parseShellArgs("")).toEqual([]);
+    expect(parseShellArgs(undefined)).toEqual([]);
+    expect(parseShellArgs("   ")).toEqual([]);
+  });
+
+  test("should parse simple arguments", () => {
+    expect(parseShellArgs("--max-turns 3")).toEqual(["--max-turns", "3"]);
+    expect(parseShellArgs("-a -b -c")).toEqual(["-a", "-b", "-c"]);
+  });
+
+  test("should handle double quotes", () => {
+    expect(parseShellArgs('--config "/path/to/config.json"')).toEqual([
+      "--config",
+      "/path/to/config.json",
+    ]);
+    expect(parseShellArgs('"arg with spaces"')).toEqual(["arg with spaces"]);
+  });
+
+  test("should handle single quotes", () => {
+    expect(parseShellArgs("--config '/path/to/config.json'")).toEqual([
+      "--config",
+      "/path/to/config.json",
+    ]);
+    expect(parseShellArgs("'arg with spaces'")).toEqual(["arg with spaces"]);
+  });
+
+  test("should handle escaped characters", () => {
+    expect(parseShellArgs("arg\\ with\\ spaces")).toEqual(["arg with spaces"]);
+    expect(parseShellArgs('arg\\"with\\"quotes')).toEqual(['arg"with"quotes']);
+  });
+
+  test("should handle mixed quotes", () => {
+    expect(parseShellArgs(`--msg "It's a test"`)).toEqual([
+      "--msg",
+      "It's a test",
+    ]);
+    expect(parseShellArgs(`--msg 'He said "hello"'`)).toEqual([
+      "--msg",
+      'He said "hello"',
+    ]);
+  });
+
+  test("should handle complex real-world example", () => {
+    const input = `--max-turns 3 --mcp-config "/Users/john/config.json" --model claude-3-5-sonnet-latest --system-prompt 'You are helpful'`;
+    expect(parseShellArgs(input)).toEqual([
+      "--max-turns",
+      "3",
+      "--mcp-config",
+      "/Users/john/config.json",
+      "--model",
+      "claude-3-5-sonnet-latest",
+      "--system-prompt",
+      "You are helpful",
+    ]);
+  });
+});