feat(FN-2477): add executable OpenClaw runtime adapter

- Replace deferred OpenClaw placeholder runtime with an executable adapter that creates sessions, prompts with fallback, describes models, and disposes safely
- Add a dedicated pi-module seam and local runtime contract types to decouple plugin compilation from engine internals while preserving runtime behavior
- Update OpenClaw plugin metadata, manifest/package descriptions, and README to reflect active execution support instead of deferred status
- Harden dashboard DevServerStore save flow against ENOENT temp-directory races and add regression coverage for project-directory removal during save

plugins/fusion-plugin-openclaw-runtime/src/runtime-adapter.ts

@@ -0,0 +1,49 @@
+import type {
+  AgentRuntime,
+  AgentRuntimeOptions,
+  AgentSession,
+  AgentSessionResult,
+} from "./types.js";
+import { createFnAgent, describeModel, promptWithFallback } from "./pi-module.js";
+
+const getModelDescription = describeModel;
+
+export class OpenClawRuntimeAdapter implements AgentRuntime {
+  readonly id = "openclaw";
+  readonly name = "OpenClaw Runtime";
+
+  async createSession(options: AgentRuntimeOptions): Promise<AgentSessionResult> {
+    return createFnAgent({
+      cwd: options.cwd,
+      systemPrompt: options.systemPrompt,
+      tools: options.tools,
+      customTools: options.customTools,
+      onText: options.onText,
+      onThinking: options.onThinking,
+      onToolStart: options.onToolStart,
+      onToolEnd: options.onToolEnd,
+      defaultProvider: options.defaultProvider,
+      defaultModelId: options.defaultModelId,
+      fallbackProvider: options.fallbackProvider,
+      fallbackModelId: options.fallbackModelId,
+      defaultThinkingLevel: options.defaultThinkingLevel,
+      sessionManager: options.sessionManager,
+      skillSelection: options.skillSelection,
+      skills: options.skills,
+    });
+  }
+
+  async promptWithFallback(session: AgentSession, prompt: string, options?: unknown): Promise<void> {
+    return promptWithFallback(session, prompt, options);
+  }
+
+  describeModel(session: AgentSession): string {
+    return getModelDescription(session);
+  }
+
+  async dispose(session: AgentSession): Promise<void> {
+    if (typeof (session as { dispose?: () => Promise<void> }).dispose === "function") {
+      await (session as { dispose: () => Promise<void> }).dispose();
+    }
+  }
+}