upgrade claude-agent-sdk to 0.2.133, drop bundled binary

Bumps @anthropic-ai/claude-agent-sdk from ^0.2.71 to ^0.2.133. The new SDK
hardens handleControlRequest against post-close transport writes (v0.2.94+),
which fixes the unhandledRejection that crashed the daemon when the SDK fired
a fire-and-forget control_request after we'd torn down the transport.

The SDK now ships per-platform Claude Code binaries via optionalDependencies
(~210 MB each). Paseo requires user-installed `claude` on PATH instead — same
posture as Codex/OpenCode:

- after-pack now prunes @anthropic-ai/claude-agent-sdk-* from the Electron
  bundle, matching the existing per-platform pruning for onnxruntime, sharp,
  and node-pty.
- claude-agent.ts gains resolveClaudeBinary() (mirrors resolveCodexBinary):
  throws with install instructions when `claude` is missing, instead of
  silently falling back to the bundled binary.
- isAvailable() now checks isCommandAvailable("claude") instead of always
  returning true.

packages/server/src/server/agent/providers/claude-agent.ts

@@ -1329,9 +1329,7 @@ export class ClaudeAgentClient implements AgentClient {
     if (command?.mode === "replace") {
       return await isCommandAvailable(command.argv[0]);
     }
-    // Default mode uses @anthropic-ai/claude-agent-sdk's bundled cli.js run
-    // via process.execPath. No external `claude` binary is required.
-    return true;
+    return await isCommandAvailable("claude");
   }
 
   async getDiagnostic(): Promise<{ diagnostic: string }> {
@@ -1383,6 +1381,16 @@ export class ClaudeAgentClient implements AgentClient {
   }
 }
 
+async function resolveClaudeBinary(): Promise<string> {
+  const found = await findExecutable("claude");
+  if (found) {
+    return found;
+  }
+  throw new Error(
+    "Claude binary not found. Install Claude Code (https://github.com/anthropics/claude-code) and ensure it is available in your shell PATH.",
+  );
+}
+
 async function resolveClaudeVersion(
   runtimeSettings?: ProviderRuntimeSettings,
 ): Promise<string | null> {
@@ -2256,11 +2264,6 @@ class ClaudeAgentSession implements AgentSession {
         ? this.config.thinkingOptionId
         : undefined;
     if (thinkingOptionId && isClaudeThinkingEffort(thinkingOptionId)) {
-      if (thinkingOptionId === "xhigh") {
-        // "xhigh" is accepted by Claude Opus 4.7 but not yet in the SDK type definitions
-        // @ts-expect-error -- SDK 0.2.71 effort type doesn't include "xhigh" yet
-        return { thinking: { type: "adaptive" }, effort: thinkingOptionId };
-      }
       return { thinking: { type: "adaptive" }, effort: thinkingOptionId };
     }
     return { thinking: undefined, effort: undefined };
@@ -2290,7 +2293,7 @@ class ClaudeAgentSession implements AgentSession {
       ],
     });
 
-    const claudeBinary = await findExecutable("claude");
+    const claudeBinary = await resolveClaudeBinary();
     this.logger.debug(
       {
         claudeBinary,
@@ -2311,7 +2314,7 @@ class ClaudeAgentSession implements AgentSession {
       allowDangerouslySkipPermissions: true,
       agents: this.defaults?.agents,
       canUseTool: this.handlePermissionRequest,
-      ...(claudeBinary ? { pathToClaudeCodeExecutable: claudeBinary } : {}),
+      pathToClaudeCodeExecutable: claudeBinary,
       // Use Claude Code preset system prompt and load CLAUDE.md files
       // Append provider-agnostic system prompt and orchestrator instructions for agents.
       systemPrompt: {