docs: rebuild README previews from 2x captures

Rework the product preview section around three real screens captured at
deviceScaleFactor 2 instead of the previous 900 px shots taken at a 75%
browser zoom, which read as blurry.

- capture the conversation workspace, the agent customization page and the
  visitor widget, then crop each one to a consistent frame
- drop the tight 480 px widget crop and its leftover gray strip
- restructure the preview section with one lead line and a caption per shot,
  and fold the local start-up steps into a shorter quick start
- keep the browser overlay out of the captures and note the method in the
  asset manifest
- finish the visible ReplyPier rename (sidebar wordmark, widget footer,
  page title, login screen, demo page) so screenshots and UI agree

.github/readme-assets/asset-manifest.json

@@ -1,38 +1,51 @@
 {
   "ui_assets_complete": true,
   "semantic_media_policy": "Use real ReplyPier interface captures; do not substitute generated product mockups.",
+  "capture_notes": "Captured at 100%-equivalent CSS layout through the shared CDP daemon at deviceScaleFactor 2, then downscaled to 1500 px wide (JPEG, quality 93, 4:4:4) for the README. Visible legacy brand strings in the UI (sidebar wordmark, widget footer, site title, page footer) were fixed in source before capture, so no text was rewritten in the browser for the shots.",
   "assets": [
     {
-      "file": "replypier-agent-customization.png",
-      "role": "AI agent appearance editor and live widget preview",
-      "source": "Saved local ReplyPier interface capture, cropped to the main workspace",
-      "alt": "ReplyPier 客服配置工作台，左侧调整聊天外观，右侧即时预览访客窗口",
-      "usage": "README product overview"
+      "file": "replypier-conversations.jpg",
+      "role": "Agent conversation workspace with a real AI answer, handoff and rating panel",
+      "source": "Local ReplyPier build, /conversations, 1600x900 CSS viewport at 2x",
+      "alt": "ReplyPier 会话工作台：访客提问、AI 依据知识库作答，转人工后由人工客服接管",
+      "usage": "README product overview (hero)"
+    },
+    {
+      "file": "replypier-agent-customization.jpg",
+      "role": "AI agent appearance editor with live visitor-widget preview",
+      "source": "Local ReplyPier build, /ai-agents?tab=customization, 1440x900 CSS viewport at 2x, cropped below the save row",
+      "alt": "ReplyPier AI 客服配置页：左侧选择聊天外观，右侧即时预览访客窗口",
+      "usage": "README configuration preview"
     },
     {
       "file": "replypier-visitor-chat.png",
       "role": "Visitor-facing chat widget",
-      "source": "User-provided real widget capture; the avatar marks were updated to the selected paper-boat brand asset",
-      "alt": "ReplyPier 网站客服聊天窗口，纸舟标志显示在客服头像与页脚图标处",
+      "source": "Local ReplyPier build, widget on /local-demo.html, transparent background capture at 2x, alpha-trimmed",
+      "alt": "ReplyPier 网站右下角的访客聊天窗口，纸舟标志显示在客服头像与页脚",
       "usage": "README visitor-side preview"
     }
   ],
   "omitted": [
     {
-      "item": "Generated service-flow illustration and 340 x 280 widget crop",
-      "reason": "Replaced with two larger, distinct interface views"
+      "item": "Previous 900 px wide captures with a 75% browser zoom",
+      "reason": "Soft text and inconsistent crops; replaced with 2x captures and a single framing rule"
     }
   ],
   "qa": [
     {
-      "file": "replypier-agent-customization.png",
+      "file": "replypier-conversations.jpg",
       "status": "passed",
-      "checks": ["chrome controls removed", "live preview visible", "alt text present"]
+      "checks": ["2x text rendering", "three-pane layout fully visible", "browser extension overlay removed from the right edge", "alt text present"]
+    },
+    {
+      "file": "replypier-agent-customization.jpg",
+      "status": "passed",
+      "checks": ["ReplyPier wordmark", "live preview visible", "no cut card edges inside the frame", "alt text present"]
     },
     {
       "file": "replypier-visitor-chat.png",
       "status": "passed",
-      "checks": ["full widget visible", "paper-boat marks applied", "message text preserved", "alt text present"]
+      "checks": ["full widget visible", "paper-boat marks applied", "footer shows ReplyPier", "transparent background", "alt text present"]
     }
   ]
 }