policy/v2: add policytester captures recorded from Tailscale SaaS

57 captures covering the alias × outcome matrix for the tests block,
recorded against a real Tailscale SaaS tailnet. Replayed by
TestPolicyTesterCompat.

Bump the check-added-large-files pre-commit threshold to 1024 KB —
captures include verbose per-node netmaps and one is 620 KB.

Updates #1803