feat: implement MCP proxy for OpenClaw tool access in contractor agent

Complete the MCP tool call chain:
- contractor-agent bridge exposes /mcp/execute endpoint for tool callbacks
- openclaw-mcp-server.mjs proxies OpenClaw tool defs to Claude as MCP tools
- sdk-adapter passes --mcp-config on first turn with all OpenClaw tools
- tool-test plugin registers contractor_echo in globalThis tool handler map
- agent-config-writer auto-sets tools.profile=full so OpenClaw sends tool defs
- Fix --mcp-config arg ordering: prompt must come before <configs...> flag

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/bridge/bootstrap.ts

@@ -0,0 +1,49 @@
+export type BootstrapInput = {
+  agentId: string;
+  openclawSessionKey: string;
+  workspace: string;
+  /** Skills XML block extracted from the OpenClaw system prompt, if any */
+  skillsBlock?: string;
+};
+
+/**
+ * Build the one-time bootstrap message injected at the start of a new Claude session.
+ * This tells Claude it is operating as an OpenClaw contractor agent.
+ * Must NOT be re-injected on every turn.
+ */
+export function buildBootstrap(input: BootstrapInput): string {
+  const lines = [
+    `You are operating as a contractor agent inside OpenClaw.`,
+    ``,
+    `## Context`,
+    `- Agent ID: ${input.agentId}`,
+    `- Session key: ${input.openclawSessionKey}`,
+    `- Workspace: ${input.workspace}`,
+    ``,
+    `## Role`,
+    `You receive tasks from OpenClaw users and complete them using your tools.`,
+    `You do not need to manage your own session context — OpenClaw handles session routing.`,
+    `Your responses go directly back to the user through OpenClaw.`,
+    ``,
+    `## Guidelines`,
+    `- Work in the specified workspace directory.`,
+    `- Be concise and action-oriented. Use tools to accomplish tasks rather than describing what you would do.`,
+    `- Each message you receive contains the latest user request. Previous context is in your session memory.`,
+    `- If a task is unclear, ask one focused clarifying question.`,
+  ];
+
+  if (input.skillsBlock) {
+    lines.push(
+      ``,
+      `## Skills`,
+      `The following skills are available. When a task matches a skill's description:`,
+      `1. Read the skill's SKILL.md using the Read tool (the <location> field is the absolute path).`,
+      `2. Follow the instructions in SKILL.md. Replace \`{baseDir}\` with the directory containing SKILL.md.`,
+      `3. Run scripts using the Bash tool, NOT the \`exec\` tool (you have Bash, not exec).`,
+      ``,
+      input.skillsBlock,
+    );
+  }
+
+  return lines.join("\n");
+}