docs(review): round-3 nits — last copy inconsistencies from Codex review

- install --proxy help text: generic network-proxy wording (was
  "Reddit/Bilibili")
- setup wizard: Reddit line no longer claims 无需配置 right before
  demanding rdt login
- README_en: bilibili proxy-era claims replaced with bili-cli reality
  (proxy section rescoped to restricted networks, doctor sample updated)
- install.md: rdt-cli example pinned to the same SHA as _RDT_GIT_SOURCE

Codex final verdict across 3 rounds: SHIP (all earlier fixes verified,
remaining items were these non-blocking nits).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent_reach/cli.py

@@ -66,7 +66,8 @@ def main():
     p_install.add_argument("--env", choices=["local", "server", "auto"], default="auto",
                            help="Environment: local, server, or auto-detect")
     p_install.add_argument("--proxy", default="",
-                           help="Residential proxy for Reddit/Bilibili (http://user:pass@ip:port)")
+                           help="Network proxy saved for agents to export as HTTP(S)_PROXY "
+                                "in restricted networks (http://user:pass@ip:port)")
     p_install.add_argument("--safe", action="store_true",
                            help="Safe mode: skip automatic system changes, show what's needed instead")
     p_install.add_argument("--dry-run", action="store_true",
@@ -1526,9 +1527,9 @@ def _cmd_setup():
     print()
 
     # Step 3: Reddit — rdt-cli
-    print("【信息】Reddit — 通过 rdt-cli 搜索和阅读，无需配置")
+    print("【信息】Reddit — 必须登录态（无零配置路径）。桌面推荐 OpenCLI；或 rdt-cli：")
     print(f"  安装：pipx install '{_RDT_GIT_SOURCE}'")
-    print("  然后运行：rdt login")
+    print("  然后运行：rdt login（需先在浏览器登录 reddit.com）")
     print()
 
     # Step 4: Groq (Whisper)