splitPathAndSel unconditionally peels a trailing :<sel> chunk whenever it
matches the read-tool selector grammar (raw, conflicts, N-M, N+K, ...). On
POSIX, filenames may legitimately contain colons, so a real file named
test:1-2 or log:raw was shredded to test/log before either read.ts or
grep.parsePathSpecs stated anything and both surfaced "Path not found".
Added splitPathAndSelPreferringLiteral(rawPath, cwd) alongside the strict
splitter: it only overrides the peel when fs.stat succeeds against the raw
path. Read (execute) and grep (parsePathSpecs) call the async variant for
non-URL paths; internal-URL splitting stays unchanged. Regression covers
splitter fallbacks, read/grep behavior on literal-colon files, and that
:1-2 selectors still work when the base file is the only real match.
Fixes#4618
roboomp
c8df93ca31