v2.3.0-sampling-params-ask-user: agent sampling params, ask_user_input in CoderPane, UX polish

Add top_p/top_k/min_p/presence_penalty to AGENTS.md frontmatter and thread
through inference (agents.ts parser → Agent type → stream-phase → sentinel
summaries). Null means omit from request body, preserving provider defaults.

Wire ask_user_input interactive card into both BooCoder frontends: the
CoderPane in BooChat's SPA (CoderMessageList now renders AskUserInputCard
instead of ToolCallLine for ask_user_input tool calls) and the standalone
coder SPA (MessageBubble + new AskUserInputCard + shadcn ui primitives).

Additional fixes: SessionLandingPage uses ChatInput with slash-command
support and lazy chat creation; Session.tsx hydrate-race fix for empty pane
promotion; AgentPicker wider dropdown with line-clamp; ModelPicker min-width;
Textarea converted to forwardRef; Recon agent added to AGENTS.md; codecontext
host port exposed in docker-compose.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/SessionLandingPage.tsx

@@ -1,8 +1,10 @@
-import { useState } from 'react';
+import { useCallback, useEffect, useState } from 'react';
 import { Archive, MessageSquare, Send, ChevronDown, ChevronRight, RotateCcw, Trash2 } from 'lucide-react';
+import { toast } from 'sonner';
 import type { Chat } from '@/api/types';
+import { api } from '@/api/client';
 import { Button } from '@/components/ui/button';
-import { Textarea } from '@/components/ui/textarea';
+import { ChatInput } from '@/components/ChatInput';
 import {
   ContextMenu,
   ContextMenuContent,
@@ -25,6 +27,8 @@ interface Props {
   chats: Chat[];
   onOpenChat: (chatId: string) => void;
   onSend: (content: string) => void;
+  /** Create a chat and return its id. Used by slash-command handler. */
+  createChat: () => Promise<{ id: string }>;
   onReopenChat: (chatId: string) => Promise<void>;
   onArchiveChat: (chatId: string) => Promise<void>;
   onRenameChat: (chatId: string, name: string) => Promise<void>;
@@ -153,12 +157,15 @@ export function SessionLandingPage({
   chats,
   onOpenChat,
   onSend,
+  projectId,
+  createChat,
   onReopenChat,
   onArchiveChat,
   onRenameChat,
   onDeleteChat,
 }: Props) {
   const [composerValue, setComposerValue] = useState('');
+  const [chatId, setChatId] = useState<string | null>(null);
   const [showArchived, setShowArchived] = useState(false);
   const [renamingId, setRenamingId] = useState<string | null>(null);
   const [renameValue, setRenameValue] = useState('');
@@ -172,13 +179,43 @@ export function SessionLandingPage({
     .filter((c) => c.status === 'archived')
     .sort((a, b) => new Date(b.updated_at).getTime() - new Date(a.updated_at).getTime());
 
-  function handleSend() {
+  // Create a chat lazily on first send or slash command.
+  const ensureChat = useCallback(async (): Promise<string> => {
+    if (chatId) return chatId;
+    try {
+      const chat = await createChat();
+      setChatId(chat.id);
+      return chat.id;
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'Failed to create chat');
+      throw err;
+    }
+  }, [chatId, createChat]);
+
+  async function handleSend() {
     const text = composerValue.trim();
     if (!text) return;
-    onSend(text);
-    setComposerValue('');
+    try {
+      const cid = await ensureChat();
+      onSend(text);
+      setComposerValue('');
+    } catch {
+      // Error already surfaced via toast.
+    }
   }
 
+  // v2.3: slash-command dispatch on landing page. Creates a chat first if
+  // one doesn't exist, then invokes the skill on that chat.
+  const handleSlashCommand = useCallback(async (skillName: string, userMessage: string) => {
+    try {
+      const cid = await ensureChat();
+      await api.chats.skillInvoke(cid, skillName, userMessage.length > 0 ? userMessage : null);
+      setComposerValue('');
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : `/${skillName} failed`);
+    }
+  }, [ensureChat]);
+
   function startRename(chat: Chat) {
     setRenamingId(chat.id);
     setRenameValue(chat.name ?? '');
@@ -293,33 +330,17 @@ export function SessionLandingPage({
         )}
       </div>
 
-      <div className="border-t px-4 py-3 flex items-end gap-2 shrink-0">
-        <Textarea
-          value={composerValue}
-          onChange={(e) => setComposerValue(e.target.value)}
-          onKeyDown={(e) => {
-            if (e.key === 'Enter' && (e.metaKey || e.ctrlKey)) {
-              e.preventDefault();
-              handleSend();
-              return;
-            }
-            if (e.key === 'Enter' && !e.shiftKey) {
-              e.preventDefault();
-              handleSend();
-            }
-          }}
-          placeholder="Start a new chat..."
-          rows={2}
-          className="resize-none min-h-[52px] max-h-[160px]"
+      {/* v2.3: ChatInput with slash-command support replaces the bare Textarea.
+          chatId is created lazily on first send/slash. */}
+      <div className="border-t px-4 py-3 shrink-0">
+        <ChatInput
+          projectId={projectId}
+          onSend={handleSend}
+          onSlashCommand={handleSlashCommand}
+          chatId={chatId ?? undefined}
+          chatLabel={chatId ? undefined : 'Chat'}
+          disabled={false}
         />
-        <Button
-          onClick={handleSend}
-          disabled={!composerValue.trim()}
-          size="icon-lg"
-          aria-label="Send"
-        >
-          <Send />
-        </Button>
       </div>
 
       <Dialog open={archiveConfirm !== null} onOpenChange={(open) => { if (!open) setArchiveConfirm(null); }}>