readTomlMeta's trailing-comment stripper found the first quote character
regardless of escaping, so a description containing \"escaped quotes\"
before a real comment got silently truncated instead of dropped. The scan
now skips a quote preceded by a backslash.
The "never walks outside" containment test passed by construction (row.file
is always built off a fixed root) and would not fail if the isUnder guard
were removed. Replaced it with two tests that actually pin the regression
risk: a skill dir and an agent .toml symlinked in from outside CODEX_HOME,
asserting the row is discovered and its content read through the link.
isUnder stays as a defensive check (matches cc-discovery.js), now commented
as such.
readTomlMeta was dropping any field with a trailing `# comment` (common in
real agents/*.toml). readSkills/readAgents/readRules used bare
isDirectory()/isFile(), which miss symlinked entries per cc-discovery.js's
own documented Dirent quirk — reused its isDirLike/isFileLike instead
(exporting isDirLike from cc-discovery.js, which wasn't previously public).
Also swapped the "never walks outside" test for one that actually exercises
a symlink escape, and dropped the unnecessary isUnder re-export.