[spec] CR-CHAT ring files use the shared trios-chat helpers instead of local copies #10841

Goal

The CR-CHAT ring files landed by #10175 drop their local copies of the shared byte helpers (ids32_equal, ids16_equal, zero_id16, bytes_equal, all_zero_bytes, approx_sqrt) and use port::trios::crates::trios-chat::common::helpers instead (#10161), as the #10175 review note asked.

Why this matters

Nineteen of the copies are byte-identical (dupe_scan flags them); the DRY rule says reuse the one that exists.

Source of truth

The sixteen ring files under specs/port/trios/crates/trios-chat/rings/CR-CHAT-03/src/ and CR-CHAT-04/src/ named in PR #10795; the helpers in specs/port/trios/crates/trios-chat/common/helpers.t27.

Deliverable

PR #10795.

Done when

The ring files carry no local copy of a shared helper; their tests pass unchanged; seals re-saved; required checks green.

How to verify

python3 -I tools/dupe_scan.py

Risks

None beyond the refactor; behaviour is unchanged by construction (identical bodies).

Links (issue, PR, ADR)

PR #10795, PR #10175, #10161; trackers #8883 and #8884.

User Scenarios

• Given the CR-CHAT ring files contain local copies of shared byte helpers, when the refactor is applied, then each ring file uses use port::trios::crates::trios-chat::common::helpers instead of its own copy.
• Given the shared helpers exist in specs/port/trios/crates/trios-chat/common/helpers.t27, when the ring files are updated, then python3 -I tools/dupe_scan.py reports zero byte-identical duplicates for those helpers.

Requirements

• FR-001: Each of the sixteen CR-CHAT ring files MUST remove local definitions of ids32_equal, ids16_equal, zero_id16, bytes_equal, all_zero_bytes, and approx_sqrt.
• FR-002: Each ring file MUST import the shared helpers via use port::trios::crates::trios-chat::common::helpers.
• FR-003: The behavioural semantics of every ring file MUST remain unchanged after the refactor.
• FR-004: All existing tests for the CR-CHAT rings MUST pass without modification.
• FR-005: Seal files MUST be re-saved after the changes.

Success Criteria

• python3 -I tools/dupe_scan.py exits with exit 0 and shows no duplicates for the six helper functions across the CR-CHAT ring files.
• The test suite for specs/port/trios/crates/trios-chat/rings/CR-CHAT-03/ and CR-CHAT-04/ passes (16 test targets).
• Seal files for all sixteen ring files are updated and committed.

Boundary

• specs/port/trios/crates/trios-chat/common/helpers.t27
• tools/dupe_scan.py