feat(youtube): route yt-dlp through SSH host for residential IP egress

Adds LAST30DAYS_YT_SSH_HOST env var (or `~/.config/last30days/.env` key).
When set, yt-dlp YouTube search invocations are wrapped as
`ssh <host> "yt-dlp ..."` so they run on a residential-IP machine.

Motivation: when last30days runs on a datacenter VPS (Hetzner,
DigitalOcean, AWS, etc.), `ytsearch:` queries return 0 results because
YouTube's bot-wall fingerprints datacenter IP ranges before any cookie
check runs. Cookies alone don't fix this — the IP reputation is checked
first. Verified across yt-dlp stable 2026.03.17 and nightly builds.

The existing fallbacks (browser cookies, residential proxy services,
excluding YouTube) all have downsides: cookies expire, proxies cost
money, exclusion loses signal. Many users with a Mac mini, Pi, or
home server can host yt-dlp on their own residential IP — this just
needs an SSH alias and a one-line env var to wire it up.

Behaviour:
- Default (env var unset): identical to before, no shape change.
- Env var set: search command list is wrapped with `ssh -o BatchMode=yes
  <host> "<shell-quoted yt-dlp invocation>"`. is_ytdlp_installed()
  returns True without a local PATH check (the binary lives on the
  remote host).
- Transcript path: when SSH-routing is on, skips the yt-dlp transcript
  path (which writes a VTT file we couldn't easily read back over SSH)
  and uses the existing _fetch_transcript_direct HTTP fallback. The
  timedtext API isn't bot-walled, so this works fine on datacenter IPs.

Setup pitfall documented in the function docstring: on macOS hosts
with Homebrew, `eval "$(/opt/homebrew/bin/brew shellenv zsh)"` must
live in ~/.zshenv (not just ~/.zprofile) — non-login SSH shells don't
source .zprofile, so without this `ssh macmini "yt-dlp ..."` returns
"command not found" while interactive SSH works fine.

Tests: 10 new cases covering env var read, whitespace stripping,
empty-value handling, command wrapping passthrough/active modes,
shlex quoting, is_ytdlp_installed short-circuit, and end-to-end
search_youtube wrapping. Full test suite: 0 new failures (the 14
pre-existing failures in test_store, test_watchlist, test_setup_openclaw,
test_safari_cookies, test_version_consistency are unchanged on main).

Verified live: 0 results → 4 real hits for "claude code" search from a
Hetzner VPS routed through a Mac mini exit node on Tailscale.

tests/test_youtube_yt.py

@@ -1,6 +1,7 @@
 """Tests for YouTube transcript highlights and yt-dlp safety flags."""
 
 import json
+import os
 import sys
 import tempfile
 import unittest
@@ -407,5 +408,93 @@ class TestSearchAndTranscribe(unittest.TestCase):
         ft_mock.assert_not_called()
 
 
+class TestYtdlpSSHRouting(unittest.TestCase):
+    """LAST30DAYS_YT_SSH_HOST routes yt-dlp invocations through SSH for residential IP."""
+
+    def setUp(self):
+        # Ensure clean env for each test
+        self._saved_env = os.environ.pop("LAST30DAYS_YT_SSH_HOST", None)
+
+    def tearDown(self):
+        os.environ.pop("LAST30DAYS_YT_SSH_HOST", None)
+        if self._saved_env is not None:
+            os.environ["LAST30DAYS_YT_SSH_HOST"] = self._saved_env
+
+    def test_no_env_var_returns_none(self):
+        """Without the env var set, _ytdlp_ssh_host returns None."""
+        self.assertIsNone(youtube_yt._ytdlp_ssh_host())
+
+    def test_env_var_returns_host(self):
+        """With LAST30DAYS_YT_SSH_HOST set, _ytdlp_ssh_host returns it."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "macmini"
+        self.assertEqual(youtube_yt._ytdlp_ssh_host(), "macmini")
+
+    def test_env_var_whitespace_stripped(self):
+        """Whitespace around the host alias is stripped."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "  macmini  "
+        self.assertEqual(youtube_yt._ytdlp_ssh_host(), "macmini")
+
+    def test_empty_env_var_falls_back_to_none(self):
+        """An empty env var is treated as unset."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = ""
+        self.assertIsNone(youtube_yt._ytdlp_ssh_host())
+
+    def test_wrap_cmd_passthrough_when_unset(self):
+        """_wrap_ytdlp_cmd returns input unchanged when SSH routing is off."""
+        cmd = ["yt-dlp", "--ignore-config", "ytsearch5:test"]
+        self.assertEqual(youtube_yt._wrap_ytdlp_cmd(cmd), cmd)
+
+    def test_wrap_cmd_prepends_ssh_when_set(self):
+        """_wrap_ytdlp_cmd prepends ssh <host> when SSH routing is on."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "macmini"
+        cmd = ["yt-dlp", "--ignore-config", "ytsearch5:test"]
+        wrapped = youtube_yt._wrap_ytdlp_cmd(cmd)
+        self.assertEqual(wrapped[0], "ssh")
+        self.assertEqual(wrapped[1], "-o")
+        self.assertEqual(wrapped[2], "BatchMode=yes")
+        self.assertEqual(wrapped[3], "macmini")
+        # Final arg is the shell-quoted command string
+        self.assertIn("yt-dlp", wrapped[4])
+        self.assertIn("ytsearch5:test", wrapped[4])
+
+    def test_wrap_cmd_quotes_args_with_spaces(self):
+        """Args containing spaces or special chars are shell-quoted."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "macmini"
+        cmd = ["yt-dlp", "ytsearch5:hello world", "--dump-json"]
+        wrapped = youtube_yt._wrap_ytdlp_cmd(cmd)
+        # shlex.quote wraps the whole arg in single quotes when it contains spaces
+        self.assertIn("'ytsearch5:hello world'", wrapped[4])
+
+    def test_is_ytdlp_installed_short_circuits_with_ssh(self):
+        """is_ytdlp_installed returns True without local check when SSH routing is on."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "macmini"
+        with mock.patch("lib.youtube_yt.shutil.which", return_value=None) as which_mock:
+            self.assertTrue(youtube_yt.is_ytdlp_installed())
+            which_mock.assert_not_called()
+
+    def test_is_ytdlp_installed_falls_through_without_ssh(self):
+        """is_ytdlp_installed checks PATH normally when SSH routing is off."""
+        with mock.patch("lib.youtube_yt.shutil.which", return_value="/usr/bin/yt-dlp"):
+            self.assertTrue(youtube_yt.is_ytdlp_installed())
+        with mock.patch("lib.youtube_yt.shutil.which", return_value=None):
+            self.assertFalse(youtube_yt.is_ytdlp_installed())
+
+    def test_search_call_routes_through_ssh(self):
+        """search_youtube wraps the yt-dlp invocation when SSH routing is on."""
+        os.environ["LAST30DAYS_YT_SSH_HOST"] = "macmini"
+        from lib.subproc import SubprocResult
+        fake_result = SubprocResult(returncode=0, stdout="", stderr="")
+        with mock.patch.object(youtube_yt.subproc, "run_with_timeout",
+                               return_value=fake_result) as run_mock:
+            youtube_yt.search_youtube("test", "2026-02-01", "2026-03-01")
+        cmd = run_mock.call_args.args[0]
+        self.assertEqual(cmd[0], "ssh")
+        self.assertEqual(cmd[3], "macmini")
+        # The shell-quoted yt-dlp invocation lives at index 4
+        self.assertIn("yt-dlp", cmd[4])
+        self.assertIn("--ignore-config", cmd[4])
+        self.assertIn("--no-cookies-from-browser", cmd[4])
+
+
 if __name__ == "__main__":
     unittest.main()