[dmitrii-f-t27]

Closes #9205

What

Ports the trios source named in the issue to specs/port/trios/crates/trios-ui/rings/UR-02/src/lib.t27, roadmap stage 6 (goal #4548). Generated seal: .trinity/seals/src_port::trios::crates::trios_ui::rings::UR_02::src::lib.json.

Ported decision, not plumbing

The functions the issue lists keep their names; the decisions inside them are pure .t27 functions with tests, and anything that touches the world keeps its name with an undefined; body no test calls. Each function carries the source line numbers it comes from.

Acceptance criteria

check	result
t27c spec-status	IMPLEMENTED
t27c gen not-implemented count	0
t27c test-report BLOCKED count	0
test blocks declared	4

  tests       4
  pass        4
  FAIL        0
  rate    100.0%

  runtime asserts per test (#6509; 0 with a folded check is CT-VERIFIED, 0 with neither is vacuous, T730):

Seal

t27c seal --save produced it: spec_path = the spec, spec_hash = the file sha256 (recomputed and matched), tests passed == total.

Boundary

The spec plus its generated seal. No other spec, no scratch file, no edit to the original.