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/acp-tool-snapshot.ts

@@ -0,0 +1,120 @@
+/**
+ * ACP tool snapshot merge + wire mapping — lifted from Paseo acp-agent.ts patterns.
+ * Stable toolCallId, merge on tool_call_update, status lifecycle for UI + DB.
+ */
+import type { ToolCall, ToolCallUpdate, ToolCallStatus, ToolKind } from '@agentclientprotocol/sdk';
+
+export type AcpToolLifecycleStatus = 'running' | 'completed' | 'failed' | 'canceled';
+
+export interface AcpToolSnapshot {
+  toolCallId: string;
+  title: string;
+  kind?: ToolKind | null;
+  status?: ToolCallStatus | null;
+  rawInput?: unknown;
+  rawOutput?: unknown;
+}
+
+export interface AcpWireMeta {
+  status: AcpToolLifecycleStatus;
+  kind?: string | null;
+  title?: string;
+  output?: unknown;
+  error?: string;
+}
+
+function coalesceDefined<T>(next: T | null | undefined, previous: T | null | undefined, fallback: T | null): T | null {
+  if (next !== undefined && next !== null) return next;
+  if (previous !== undefined && previous !== null) return previous;
+  return fallback;
+}
+
+export function mergeToolSnapshot(
+  toolCallId: string,
+  update: ToolCall | ToolCallUpdate,
+  previous?: AcpToolSnapshot,
+): AcpToolSnapshot {
+  return {
+    toolCallId,
+    title: update.title ?? previous?.title ?? toolCallId,
+    kind: update.kind ?? previous?.kind ?? null,
+    status: update.status ?? previous?.status ?? null,
+    rawInput: update.rawInput !== undefined ? update.rawInput : previous?.rawInput,
+    rawOutput: update.rawOutput !== undefined ? update.rawOutput : previous?.rawOutput,
+  };
+}
+
+export function mapToolLifecycleStatus(
+  status: ToolCallStatus | null | undefined,
+  rawOutput?: unknown,
+): AcpToolLifecycleStatus {
+  if (rawOutput === 'canceled') return 'canceled';
+  switch (status) {
+    case 'completed':
+      return 'completed';
+    case 'failed':
+      return 'failed';
+    case 'pending':
+    case 'in_progress':
+    default:
+      return 'running';
+  }
+}
+
+function readErrorMessage(rawOutput: unknown): string | undefined {
+  if (typeof rawOutput === 'string' && rawOutput.trim()) return rawOutput;
+  if (rawOutput && typeof rawOutput === 'object' && !Array.isArray(rawOutput)) {
+    const rec = rawOutput as Record<string, unknown>;
+    const msg = rec.message ?? rec.error ?? rec.reason;
+    if (typeof msg === 'string' && msg.trim()) return msg;
+  }
+  return undefined;
+}
+
+function asRecord(value: unknown): Record<string, unknown> {
+  if (value && typeof value === 'object' && !Array.isArray(value)) {
+    return value as Record<string, unknown>;
+  }
+  return {};
+}
+
+export function snapshotToWireToolCall(snapshot: AcpToolSnapshot): {
+  id: string;
+  name: string;
+  args: Record<string, unknown>;
+} {
+  const lifecycle = mapToolLifecycleStatus(snapshot.status, snapshot.rawOutput);
+  const input = asRecord(snapshot.rawInput);
+  const error = lifecycle === 'failed' ? readErrorMessage(snapshot.rawOutput) : undefined;
+  const meta: AcpWireMeta = {
+    status: lifecycle,
+    kind: snapshot.kind ?? null,
+    title: snapshot.title,
+    ...(snapshot.rawOutput !== undefined ? { output: snapshot.rawOutput } : {}),
+    ...(error ? { error } : {}),
+  };
+  return {
+    id: snapshot.toolCallId,
+    name: String(snapshot.kind ?? snapshot.title),
+    args: { ...input, _acp: meta },
+  };
+}
+
+export function snapshotToPartPayload(snapshot: AcpToolSnapshot): {
+  id: string;
+  name: string;
+  args: Record<string, unknown>;
+} {
+  const wire = snapshotToWireToolCall(snapshot);
+  return { id: wire.id, name: wire.name, args: wire.args };
+}
+
+export function synthesizeCanceledSnapshots(snapshots: Iterable<AcpToolSnapshot>): AcpToolSnapshot[] {
+  const out: AcpToolSnapshot[] = [];
+  for (const snapshot of snapshots) {
+    if (mapToolLifecycleStatus(snapshot.status) === 'running') {
+      out.push({ ...snapshot, status: 'failed', rawOutput: snapshot.rawOutput ?? 'canceled' });
+    }
+  }
+  return out;
+}