v2.2-paseo-providers: Paseo provider stack + v2.2.1 pane-scoped chat fixes

Ship Paseo-equivalent provider snapshot, AgentComposerBar, ACP dispatch
rewrite with streaming/persist, permission prompts, and agent commands.
Follow-up: pane-scoped chat resolution, CoderMessageList tool timeline,
WS user-delta replace, and inference orphan tool_call stripping.
Archive openspec v2-2; update CHANGELOG and CURRENT.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/coder/src/services/host-exec.ts

@@ -0,0 +1,66 @@
+/**
+ * Local shell exec on the BooCoder host (replaces deprecated ssh.ts for worktrees).
+ */
+import { spawn } from 'node:child_process';
+
+export interface HostExecResult {
+  exitCode: number;
+  stdout: string;
+  stderr: string;
+}
+
+export async function hostExec(
+  command: string,
+  opts?: { signal?: AbortSignal; timeoutMs?: number },
+): Promise<HostExecResult> {
+  return new Promise<HostExecResult>((resolve, reject) => {
+    const child = spawn('bash', ['-lc', command], {
+      stdio: ['pipe', 'pipe', 'pipe'],
+    });
+
+    let stdout = '';
+    let stderr = '';
+    let killed = false;
+
+    child.stdout!.on('data', (chunk: Buffer) => { stdout += chunk.toString(); });
+    child.stderr!.on('data', (chunk: Buffer) => { stderr += chunk.toString(); });
+
+    const cleanup = () => {
+      if (!killed) {
+        killed = true;
+        child.kill('SIGTERM');
+      }
+    };
+
+    if (opts?.signal) {
+      if (opts.signal.aborted) {
+        cleanup();
+        reject(new Error('host exec aborted before start'));
+        return;
+      }
+      opts.signal.addEventListener('abort', cleanup, { once: true });
+    }
+
+    let timer: ReturnType<typeof setTimeout> | undefined;
+    if (opts?.timeoutMs) {
+      timer = setTimeout(() => {
+        cleanup();
+        reject(new Error(`host exec timed out after ${opts.timeoutMs}ms`));
+      }, opts.timeoutMs);
+    }
+
+    child.on('close', (code) => {
+      if (timer) clearTimeout(timer);
+      if (opts?.signal) opts.signal.removeEventListener('abort', cleanup);
+      resolve({ exitCode: code ?? 1, stdout, stderr });
+    });
+
+    child.on('error', (err) => {
+      if (timer) clearTimeout(timer);
+      if (opts?.signal) opts.signal.removeEventListener('abort', cleanup);
+      reject(err);
+    });
+
+    child.stdin!.end();
+  });
+}