GHSA-4xrr-hq4w-6vf4: Caddy: Improper sanitization of glob characters in file matcher may lead to bypassing security protections

Caddy's file matcher doesn't properly escape backslashes when sanitizing glob patterns (special characters used for file matching), which allows attackers to bypass security protections. For example, a reverse proxy blocking `/documents/*` can be bypassed by requesting `/do%5ccuments/` (where `%5c` is a backslash) because the backslash in the glob pattern is treated as an escape character and ignored before non-special characters.