feat(db,admin): Add logo URL support and refactor bot schema with owner relationships

- Add logo_url column to nodes table for custom branding
- Refactor bots table to use owner_id foreign key relationship with users
- Add is_bot and bot_owner_id columns to users table for bot account tracking
- Add bot_id foreign key to posts table for bot-generated content tracking
- Create database indexes on owner_id, bot_id, is_bot, and bot_owner_id for query performance
- Remove bot handle, bio, avatar_url, and cryptographic keys from bots table (moved to user accounts)
- Update bot_content_sources schema and remove fetch_interval_minutes column
- Fix bot_content_items foreign key constraint with set null on delete
- Remove hardcoded NODE_NAME and NODE_DESCRIPTION from environment configuration
- Update admin panel, bot settings, and layout components to support new schema
- Add AccentColorContext and ToastContext for improved UI state management
- Update PostCard, Sidebar, RightSidebar, and LayoutWrapper components for context integration

src/lib/contexts/AccentColorContext.tsx

@@ -0,0 +1,67 @@
+'use client';
+
+import { createContext, useContext, useEffect, useState, useCallback, ReactNode } from 'react';
+
+interface AccentColorContextType {
+    accentColor: string;
+    refreshAccentColor: () => void;
+}
+
+const AccentColorContext = createContext<AccentColorContextType | null>(null);
+
+function applyAccentColor(color: string) {
+    const cleaned = color.trim();
+    const normalized = cleaned.startsWith('#') ? cleaned : `#${cleaned}`;
+    const hexMatch = /^#([0-9a-fA-F]{6})$/.exec(normalized);
+    if (!hexMatch) return;
+
+    const hex = hexMatch[1];
+    const r = parseInt(hex.slice(0, 2), 16);
+    const g = parseInt(hex.slice(2, 4), 16);
+    const b = parseInt(hex.slice(4, 6), 16);
+
+    const mix = (channel: number, target: number, amount: number) =>
+        Math.round(channel + (target - channel) * amount);
+
+    const hover = `rgb(${mix(r, 255, 0.12)}, ${mix(g, 255, 0.12)}, ${mix(b, 255, 0.12)})`;
+    const muted = `rgba(${r}, ${g}, ${b}, 0.12)`;
+
+    const root = document.documentElement;
+    root.style.setProperty('--accent', `#${hex}`);
+    root.style.setProperty('--accent-hover', hover);
+    root.style.setProperty('--accent-muted', muted);
+}
+
+export function AccentColorProvider({ children }: { children: ReactNode }) {
+    const [accentColor, setAccentColor] = useState('#00D4AA');
+
+    const refreshAccentColor = useCallback(() => {
+        fetch('/api/node', { cache: 'no-store' })
+            .then((res) => res.json())
+            .then((data) => {
+                if (data?.accentColor) {
+                    setAccentColor(data.accentColor);
+                    applyAccentColor(data.accentColor);
+                }
+            })
+            .catch(() => {});
+    }, []);
+
+    useEffect(() => {
+        refreshAccentColor();
+    }, [refreshAccentColor]);
+
+    return (
+        <AccentColorContext.Provider value={{ accentColor, refreshAccentColor }}>
+            {children}
+        </AccentColorContext.Provider>
+    );
+}
+
+export function useAccentColor() {
+    const context = useContext(AccentColorContext);
+    if (!context) {
+        throw new Error('useAccentColor must be used within an AccentColorProvider');
+    }
+    return context;
+}