feat: content defaults — applied on channel creation

DB: app_settings category=content (10 keys)
channels.js: createChannel reads DEFAULT_* from settings and applies to new channel
  DEFAULT_POST_LANGUAGE/LENGTH/STYLE/GOAL → channel.goal, language
  DEFAULT_IMAGE_ENABLED → channel.image_enabled
  DEFAULT_AI_STYLE_PROMPT → channel.ai_style_prompt
  DEFAULT_AUTO_DRAFT_COUNT/TIME → channel.auto_draft_count/time
channels: image_enabled BOOLEAN DEFAULT true

src/services/channels.js

@@ -47,18 +47,42 @@ async function createChannel(userId, data) {
 
   if (!name) throw new Error('name is required');
 
-  const client = await require('../config/db').query;
+  // Загружаем контентные дефолты
+  const settingsSvc = require('./settings');
+  const [
+    defLanguage, defLength, defStyle, defGoal,
+    defImageEnabled, defEmojiEnabled, defHashtags,
+    defDraftCount, defDraftTime, defStylePrompt,
+  ] = await Promise.all([
+    settingsSvc.get('DEFAULT_POST_LANGUAGE',    'ru'),
+    settingsSvc.get('DEFAULT_POST_LENGTH',      'medium'),
+    settingsSvc.get('DEFAULT_POST_STYLE',       'informative'),
+    settingsSvc.get('DEFAULT_POST_GOAL',        'educational'),
+    settingsSvc.get('DEFAULT_IMAGE_ENABLED',    'true'),
+    settingsSvc.get('DEFAULT_EMOJI_ENABLED',    'true'),
+    settingsSvc.get('DEFAULT_HASHTAGS_IN_POST', 'false'),
+    settingsSvc.get('DEFAULT_AUTO_DRAFT_COUNT', '3'),
+    settingsSvc.get('DEFAULT_AUTO_DRAFT_TIME',  '08:00'),
+    settingsSvc.get('DEFAULT_AI_STYLE_PROMPT',  ''),
+  ]);
 
-  // INSERT channel
+  // INSERT channel с дефолтами из системных настроек
   const { rows: chRows } = await query(
     `INSERT INTO channels
-       (user_id, name, tg_channel_id, tg_username, bot_token, niche, audience, goal, language, region)
-     VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10)
+       (user_id, name, tg_channel_id, tg_username, bot_token, niche, audience, goal, language, region,
+        image_enabled, ai_style_prompt, auto_draft_count, auto_draft_time)
+     VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14)
      RETURNING *`,
     [
       userId, name, tg_channel_id || null, tg_username || null, bot_token || null,
-      niche || null, audience || null, goal || 'educational',
-      language || 'ru', region || 'ru',
+      niche || null, audience || null,
+      goal || defGoal,
+      language || defLanguage,
+      region || 'ru',
+      defImageEnabled === 'true',
+      defStylePrompt || null,
+      parseInt(defDraftCount) || 3,
+      defDraftTime || '08:00',
     ]
   );
   const channel = chRows[0];
@@ -75,9 +99,9 @@ async function createChannel(userId, data) {
       style.tone_custom || null,
       style.formality || 'informal',
       style.humor || 'moderate',
-      style.post_length || 'medium',
+      style.post_length || defLength,
       style.structure || 'mixed',
-      style.emoji_level || 'moderate',
+      style.emoji_level || (defEmojiEnabled === 'true' ? 'moderate' : 'none'),
       style.hashtags_mode || 'end',
       style.cta_mode || 'sometimes',
       JSON.stringify(style.example_posts || []),