feat: unified context panel, remove tabs, context-aware layout

- Merged AI Assistant + Lead 360 tabs into single context-aware panel
- Context section shows: lead profile, AI insight (live from event bus), appointments, activity
- "On call with" banner only shows during active calls (isInCall prop)
- AI Chat always available at bottom of panel
- Phase 1 only — AI Chat panel needs full redesign with Vercel AI SDK tool calling (Phase 2)

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

src/components/base/select/select-shared.tsx

@@ -0,0 +1,49 @@
+import type { FC, ReactNode } from "react";
+import { createContext } from "react";
+
+export type SelectItemType = {
+    /** Unique identifier for the item. */
+    id: string | number;
+    /** The primary display text. */
+    label?: string;
+    /** Avatar image URL. */
+    avatarUrl?: string;
+    /** Whether the item is disabled. */
+    isDisabled?: boolean;
+    /** Secondary text displayed alongside the label. */
+    supportingText?: string;
+    /** Leading icon component or element. */
+    icon?: FC | ReactNode;
+};
+
+export interface CommonProps {
+    /** Helper text displayed below the input. */
+    hint?: string;
+    /** Field label displayed above the input. */
+    label?: string;
+    /** Tooltip text for the help icon next to the label. */
+    tooltip?: string;
+    /**
+     * The size of the component.
+     * @default "md"
+     */
+    size?: "sm" | "md" | "lg";
+    /** Placeholder text when no value is selected. */
+    placeholder?: string;
+    /** Whether to hide the required indicator from the label. */
+    hideRequiredIndicator?: boolean;
+}
+
+export const sizes = {
+    sm: {
+        root: "py-2 pl-3 pr-2.5 gap-2 *:data-icon:size-4 *:data-icon:stroke-[2.25px]",
+        withIcon: "",
+        text: "text-sm",
+        textContainer: "gap-x-1.5",
+        shortcut: "pr-2.5",
+    },
+    md: { root: "py-2 px-3 gap-2 *:data-icon:size-5", withIcon: "", text: "text-md", textContainer: "gap-x-1.5", shortcut: "pr-2.5" },
+    lg: { root: "py-2.5 px-3.5 gap-2 *:data-icon:size-5", withIcon: "", text: "text-md", textContainer: "gap-x-1.5", shortcut: "pr-3" },
+};
+
+export const SelectContext = createContext<{ size: "sm" | "md" | "lg" }>({ size: "md" });