perf: bound token probes and reuse lookahead analysis (#2829)

Keep complete single-token restrictions at depth one and remove one
investigated redundant destination guard. Add a complete decision inventory,
content-addressed snapshots and incremental FIRST/FOLLOW and site reuse.

Bind full review evidence to caller reachability, transitive grammar and
opaque inputs. Keep local token certificates explicit and limited in scope.

Preserve the inherited test process environment for Windows Git fixtures and
refresh the two review bindings after the watched build input changes.

Signed-off-by: 付典 <fudianchn@gmail.com>

Author: fudianchn