zig-test execution level: 37/69 tri-net gens pass; three finding classes in the rest #1928

Running zig test on tri-net's committed gen/zig (a level above ast-check) with two emission fixes in the linked PR (dead types.zig import skipped when unreferenced; test asserts emit @panic instead of @compileError, which fired whenever a runtime-condition branch was ANALYZED): 37/69 files compile AND pass their test blocks.

The 32 remaining split into three classes, all REAL findings the execution level exists to catch:

1. The t27 saturation idiom is Zig-fatal: let sum = a + b; if (sum < a) ... panics on overflow at the + (checked semantics) before the guard runs -- specs need +% for the probe add (tri_challenge, timer, packet_queue...). Same class as the tri_sha256 +% migration.
2. Genuine test failures at runtime (e.g. etx 'dead link should be infinite') -- semantic bugs invisible to every syntax-level gate.
3. Small emission tails: unused test-binding consts when the assert folds away (hello), a stray @compilelog (wire).

tri-net gates the passing 37 in CI and ratchets as classes 1-3 clear.

User Scenarios

• Given the tri-net gen/zig suite at execution level, when zig test runs on all 69 files, then 37 pass and 32 fail across three finding classes (saturation overflow, semantic runtime failures, emission tails)
• Given a spec using the saturation idiom let sum = a + b; if (sum < a) ..., when compiled to Zig with checked arithmetic, then the + panics before the guard runs unless the spec uses +% for the probe add
• Given specs with emission tails (unused test-binding consts, stray @compileLog), when the assert folds away, then the emitted Zig contains dead code that fails compilation or clutters output

Requirements

FR-001: Specs for tri_challenge, timer, packet_queue, and tri_sha256 MUST replace saturation + with +% so the probe add wraps instead of panicking
FR-002: Specs for etx (and any component with genuine runtime test failures) MUST correct the semantic bug so the test assertion holds at runtime
FR-003: Specs for hello and wire MUST remove unused test-binding consts and stray @compileLog so emission is clean when asserts fold away
FR-004: The t27 compiler MUST continue to gate the passing 37 files in CI and ratchet coverage as classes 1–3 clear

Success Criteria

• zig test on tri-net gen/zig executes all 69 files and exits 0
• 69 test files compile AND pass their test blocks (up from 37)
• Zero saturation overflow panics in probe adds across tri_challenge, timer, packet_queue, tri_sha256 specs
• Zero runtime assertion failures in etx and related components
• Zero unused const or @compileLog emission tails in hello and wire specs

Boundary

• specs/tools/tri/test.t27
• specs/tools/trinity/tri/test.t27