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/coder/web/src/components/ui/button.tsx

@@ -0,0 +1,35 @@
+import * as React from 'react';
+
+export interface ButtonProps
+  extends React.ButtonHTMLAttributes<HTMLButtonElement> {
+  variant?: 'default' | 'destructive' | 'outline' | 'secondary' | 'ghost' | 'link';
+  size?: 'default' | 'sm' | 'lg' | 'icon';
+}
+
+const variantClasses: Record<string, string> = {
+  default: 'bg-primary text-primary-foreground hover:bg-primary/90',
+  destructive: 'bg-destructive text-destructive-foreground hover:bg-destructive/90',
+  outline: 'border border-input bg-background hover:bg-accent hover:text-accent-foreground',
+  secondary: 'bg-secondary text-secondary-foreground hover:bg-secondary/80',
+  ghost: 'hover:bg-accent hover:text-accent-foreground',
+  link: 'text-primary underline-offset-4 hover:underline',
+};
+
+const sizeClasses: Record<string, string> = {
+  default: 'h-9 px-4 py-2',
+  sm: 'h-8 rounded-md px-3 text-xs',
+  lg: 'h-10 rounded-md px-8',
+  icon: 'h-9 w-9',
+};
+
+const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
+  ({ className, variant = 'default', size = 'default', ...props }, ref) => {
+    const base =
+      'inline-flex items-center justify-center whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring/40 disabled:pointer-events-none disabled:opacity-60';
+    const cls = [base, variantClasses[variant] ?? '', sizeClasses[size] ?? '', className ?? ''].join(' ');
+    return <button className={cls} ref={ref} {...props} />;
+  },
+);
+Button.displayName = 'Button';
+
+export { Button };