Denying the whole <root>/profiles tree 403'd legitimate named-profile workspace
media (<base>/profiles/p1/workspace/shot.png). Fix: remove 'profiles' from
_DENY_SUBDIRS and instead enumerate each <root>/profiles/<name> directory as its
own Hermes root — so each profile's sensitive subdirs (sessions/memories/cron/
logs/checkpoints/backups) + secret filenames are denied, while that profile's
workspace/ is allowed via the carve-out. Adds a regression test: named-profile
workspace media serves, profile + sibling-profile auth.json stay 403.