fix(node): a member is told a media tool failed, not what ffmpeg said

Stream, transcode and subtitle failures sent the exception's text — operator
paths, versions — to the member. Fixed messages now, the cause in the log
(F-24).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/packages/meshbay-node/tests/test_member_errors_are_plain.py b/packages/meshbay-node/tests/test_member_errors_are_plain.py
new file mode 100644
index 0000000..e144e9b
--- /dev/null
+++ b/packages/meshbay-node/tests/test_member_errors_are_plain.py
@@ -0,0 +1,22 @@
+"""
+What a member is told when the media tools fail: that it failed.
+
+An exception's text from ffmpeg or ffprobe names the operator's paths, versions
+and the libraries the build has; the member who asked needs none of it, and the
+operator finds it in their log. Read from the source, because what matters is
+that no reply in these handlers carries an exception's text at all.
+"""
+
+import re
+from pathlib import Path
+
+APPS = Path(__file__).resolve().parents[1] / "src" / "meshbay_node" / "transport" / "webrtc"
+
+
+def test_no_reply_to_a_member_carries_an_exceptions_text():
+    offenders = []
+    for path in APPS.rglob("*.py"):
+        text = path.read_text(encoding="utf-8")
+        for m in re.finditer(r'"detail":\s*(f"[^"]*\{e\}[^"]*"|str\(e\))', text):
+            offenders.append(f"{path.name}: {m.group(0)}")
+    assert not offenders, offenders