Compile grant app fields into CapGrant FilterRules matching Tailscale
SaaS behavior. Key changes:
- Generate CapGrant rules in compileFilterRules and
compileGrantWithAutogroupSelf, with node-specific /32 and /128
Dsts for autogroup:self grants
- Add reversed companion rules for drive→drive-sharer and
relay→relay-target capabilities, ordered by original cap name
- Narrow broad CapGrant Dsts to node-specific prefixes in
ReduceFilterRules via new reduceCapGrantRule helper
- Skip merging CapGrant rules in mergeFilterRules to preserve
per-capability structure
- Remove ip+app mutual exclusivity validation (Tailscale accepts both)
- Add semantic JSON comparison for RawMessage types and netip.Prefix
comparators in test infrastructure
Reduces grant compat test skips from 99 to 41 (58 newly passing).
Updates #2180
Add exit route check in ReduceFilterRules to prevent exit nodes from receiving packet filter rules for destinations that only overlap via exit routes. Remove resolved SUBNET_ROUTE_FILTER_RULES grant skip entries and update error message formatting for grant validation.
Updates #2180
