[CompleteDotTech]

Refs #91. This is a bounded Render3D foundation; #91 and the full renderer mission #16 remain open.

Render requests now have strict, additive contracts for exact frame time, settings, source snapshots, job/result state and backend/verifier identity. The native rig source adapter creates an immutable exact-byte snapshot, validates present skeleton/controller/skin/animation semantics through their existing owners, and rechecks the frozen closure before use. A request-bound frame plan rejects changed snapshot bytes. Existing 2D rendering and source/review formats remain unchanged.

The implementation includes six generated schemas, typed diagnostics, exact rational frame/subframe and coordinate conversion, a source-only CLI, and explicit native gate registration. It preserves existing destinations through the repository's exclusive publication primitive. It rejects incomplete source closures, hashes/path aliases/symlinks, malformed or unsupported settings, unverified completion claims and invalid present rig semantics. Static unrigged source imports remain supported.

Validation at head cba832ea6e3455c188478285da6a1b9896db2aca:

• 39 Render3D tests pass, including 24 independently authored tests and regressions for full-diff review findings.
• 70 native schema/math gate tests pass in the recorded dependency-equipped test environment; schema generation check passes.
• 31 production-contract, 20 production-renderer and five compatibility tests pass. The compatibility probe discovers 831 legacy 2D tests without optional imports; this is not a full 831-test run.
• An actual synthetic native robot with 706 vertices / 1,368 triangles is captured and reloaded through the CLI; the returned creation/verification snapshot records match.
• The initial default-environment native gate lacked pygltflib. That failure is retained; the subsequent test environment is recorded accurately and is not described as matching every declared dependency pin.

Independent full-diff review exposed three numeric admission issues, a native source semantic validation gap and a source-verification error translation gap. Corrective commits and focused regressions preserve that history. Exact evidence is in tests/results/render3d-foundation-20261025.json; the reference guide maps implemented behavior and outstanding acceptance.

Remaining boundaries: full Scene3D adaptation depends on its owner in #59. No Blender renderer, PNG/EXR decoder, scheduler, cache-recovery implementation, GPU execution, silent-video export, hosted-CI pass or production visual approval is claimed. The backend/verifier APIs are contracts for that downstream work. No workflows were enabled or changed.

Final independent full-diff review passed at cba832ea6e3455c188478285da6a1b9896db2aca, with no unresolved actionable findings. A read-only pre-publication recheck confirmed all 18 reviewed file hashes and the five retained passing check logs. Hosted CI is not asserted by this local review.