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/web/src/pages/Session.tsx

@@ -190,6 +190,9 @@ function SessionInner({ sessionId }: { sessionId: string }) {
     [addSplitPane, isMobile, navigate, location.pathname, location.search],
   );
 
+  const activePaneKind = panes[activePaneIdx]?.kind;
+  const showSessionModelPicker = activePaneKind !== 'coder';
+
   // v1.10.3 keyboard shortcuts. Window-level keydown so they fire from
   // anywhere in the session view. Only Cmd/Ctrl-Shift-C defers to the xterm
   // (which has its own copy binding for that combo); everything else fires
@@ -351,7 +354,7 @@ function SessionInner({ sessionId }: { sessionId: string }) {
                 )}
               </div>
 
-              {session && (
+              {session && showSessionModelPicker && (
                 <ModelPicker
                   value={session.model}
                   onChange={async (model) => {
@@ -449,7 +452,7 @@ function SessionInner({ sessionId }: { sessionId: string }) {
             )}
 
             <div className="ml-auto shrink-0">
-              {session && (
+              {session && showSessionModelPicker && (
                 <div className="inline-flex items-center rounded-full bg-muted/40 hover:bg-muted/70 px-1">
                   <ModelPicker
                     value={session.model}
@@ -478,6 +481,7 @@ function SessionInner({ sessionId }: { sessionId: string }) {
           chatsHook={chatsHook}
           session={session}
           project={project}
+          onAddPane={addPaneAndSwitch}
         />
       )}
     </div>