fix(review): round-2 findings — dead proxy key, unbounded transcribe, doc pins

- configure proxy: the bilibili_proxy key lost its only reader when yt-dlp
  exited the bilibili channel (PR5), leaving docs promising an unlock that
  did nothing. Now saves a generic `proxy` key (legacy key kept in sync),
  and every wording — CLI output, server tip, install.md quick reference —
  says what it really is: a saved address agents read to export
  HTTP(S)_PROXY, not an unlock switch
- transcribe: subprocess calls get timeouts (yt-dlp download 1800s, ffmpeg
  600s) so a stalled network read can't hang the CLI forever
- docs/update.md: rdt-cli install uses the same pinned git SHA as the
  code's _RDT_GIT_SOURCE instead of floating HEAD
- probe.py: documented as side-effect-free-probes-only (retries re-run
  verbatim with no backoff)

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

agent_reach/cli.py

@@ -226,10 +226,11 @@ def _cmd_install(args):
     # Apply explicit flags
     if args.proxy:
         if dry_run:
-            print(f"[dry-run] Would configure proxy for Bilibili")
+            print(f"[dry-run] Would save network proxy")
         else:
-            config.set("bilibili_proxy", args.proxy)
-            print(f"✅ Proxy configured for Bilibili")
+            config.set("proxy", args.proxy)
+            config.set("bilibili_proxy", args.proxy)  # legacy key
+            print(f"✅ 代理已保存（Agent 访问受限网络时使用）")
 
     # ── Install core system dependencies (lightweight, always) ──
     print()
@@ -298,9 +299,9 @@ def _cmd_install(args):
     # Environment-specific advice
     if env == "server":
         print()
-        print("Tip: Bilibili may block server IPs.")
-        print("   Reddit: rdt-cli works without proxy (pipx install rdt-cli).")
-        print("   For Bilibili full access: agent-reach configure proxy http://user:pass@ip:port")
+        print("Tip: 部分平台对服务器 IP 有风控。")
+        print("   Reddit 必须登录态（rdt-cli + Cookie，见 doctor 提示），中国大陆网络还需代理。")
+        print("   保存代理供 Agent 使用：agent-reach configure proxy http://user:pass@ip:port")
         print("   Cheap option: https://www.webshare.io ($1/month)")
 
     # Test channels
@@ -1036,9 +1037,14 @@ def _cmd_configure(args):
         return
 
     if args.key == "proxy":
+        # Generic network proxy for restricted environments. Nothing reads
+        # this key at runtime — agents read it back and export HTTP(S)_PROXY
+        # before invoking upstream tools (see docs/install.md). The legacy
+        # bilibili_proxy key is kept in sync for older configs.
+        config.set("proxy", value)
         config.set("bilibili_proxy", value)
-        print(f"✅ Proxy configured for Bilibili!")
-        print("  Note: Reddit 已改为通过 rdt-cli 访问，无需代理。")
+        print("✅ 代理已保存（供 Agent 在访问 Reddit/Twitter 等需要代理的网络时设置 HTTP_PROXY/HTTPS_PROXY）")
+        print("  Note: B站走 bili-cli，国内网络无需代理。")
 
     elif args.key == "twitter-cookies":
         # Accept two formats:

agent_reach/probe.py

@@ -53,6 +53,10 @@ def probe_command(
 ) -> ProbeResult:
     """Actually execute `cmd *args` and classify the result.
 
+    Intended for SIDE-EFFECT-FREE health probes only (version/status
+    commands): retries re-run the command verbatim with no backoff, so a
+    non-idempotent command would repeat its effect.
+
     package: pip/pipx package name used in the broken-install hint
              (defaults to cmd).
     """

agent_reach/transcribe.py

@@ -58,9 +58,16 @@ def _require(binary: str) -> None:
         raise MissingDependency(f"{binary} not found in PATH")
 
 
-def _run(cmd: List[str]) -> None:
-    """Run a subprocess, raising TranscribeError on nonzero exit."""
-    proc = subprocess.run(cmd, capture_output=True, text=True)
+def _run(cmd: List[str], timeout: int = 600) -> None:
+    """Run a subprocess, raising TranscribeError on nonzero exit or timeout.
+
+    cmd carries user-supplied URLs/paths into yt-dlp/ffmpeg — a stalled
+    network read or a hung probe must not block the CLI forever.
+    """
+    try:
+        proc = subprocess.run(cmd, capture_output=True, text=True, timeout=timeout)
+    except subprocess.TimeoutExpired:
+        raise TranscribeError(f"{cmd[0]} timed out after {timeout}s")
     if proc.returncode != 0:
         raise TranscribeError(
             f"{cmd[0]} failed (exit {proc.returncode}): {proc.stderr.strip()[:300]}"
@@ -82,7 +89,8 @@ def download_audio(url: str, out_dir: Path) -> Path:
             "-o",
             str(template),
             url,
-        ]
+        ],
+        timeout=1800,  # long podcasts over slow networks — generous but bounded
     )
     files = sorted(out_dir.glob("source.*"))
     if not files: