*tag-trigger-count* hash table tracks per-session tag triggers.
tag-trigger-record increments count, called from
dispatcher-privacy-severity on each matched tag. /tags shows
trigger count per tag.
tag-categories-load now falls back to PRIVACY_FILTER_TAGS env var
when TAG_CATEGORIES is not set (backward compat). All entries
default to :block severity.
- security-dispatcher: *tag-trigger-count*, tag-trigger-record,
updated tag-categories-load, wired dispatcher-privacy-severity
+2 tests (trigger record, privacy fallback)
- channel-tui-main: /tags shows trigger counts
- Core: 88/88 TUI Main: 102/102