Development record

The lint brief states the wrong exit codes for the two tree gates. .abcd/development/brief/05-internals/06-lint.md:48 says record-lint and abcd lint docs follow the tri-state grammar, blocker 2, warn 1, clean 0, and the severity table at line 34 says a warn finding raises the exit code to 1. The code does neither: cmd/record-lint/main.go:144 exits 1 on any blocker and 2 only when the lint could not run, internal/surface/cli/cli.go:955 makes abcd lint docs exit 1 on a blocker, and neither gate raises its exit code for warnings alone. The 2/1/0 tri-state belongs to bare abcd lint (internal/surface/cli/lint.go:76). A CI job written from the brief that keys on exit 2 for a blocker would pass a tree full of blockers.