**Overall Verdict:** Strong Accept — The submission is complete, internally consistent, professionally constructed, and supports a deterministic end-to-end implementation and objective evaluation workflow.

**Completeness Check:**
- Instruction: Complete — The motion convention, interval semantics, coordinate handling, bilinear splatting, normalization, output schemas, runtime command, restrictions, and determinism requirements are explicit.
- Inputs: Complete — The input archive contains the declared HDF5 event stream, calibration, 20-window CSV, Boolean validity mask, documentation, schema helper, pinned dependencies, licensing, and integrity manifest.
- Toolchain: Complete — The specified Linux/Python CPU stack is freely obtainable, pinned, compatible with the supplied formats, and requires neither network access nor specialized hardware at runtime.
- Reference output: Complete — The segregated gold CSV has 20 matching windows and 440,758 total events; the NPZ contains exactly `positive` and `negative` little-endian float32 arrays with shape `(20,260,346)`, finite nonnegative values, and normalized per-plane mass.
- Rubric: Complete — The offline evaluator implements all stated schema, event-count, angular-velocity, integrated-orientation, blurred-IWE, and two-run determinism gates with exact thresholds and machine-readable results.

**File and Task Reachability:**
Attachment classification: reachable. Task classification: reachable. I inspected `event_rotation_input_v1.zip` and `event_rotation_reference_v1.zip`, including their complete inventories, integrity manifests, licenses, input documentation and schemas, calibration, windows, validity mask, HDF5 evidence, reference CSV and NPZ, evaluator source and tests, grading configuration, diagnostics, and provenance generator/configuration. Both archive byte counts match the manifest; both are readable, unencrypted, free of unsafe paths or special filesystem entries, and all internal checksums match. The solver-visible input is separated from the reference motion schedule, gold outputs, generator, and evaluator. No manifest attachment was unreviewed. Native HDF5 dataset traversal and video frame decoding were unavailable in the review environment; the HDF5 file was instead corroborated through its valid signature, embedded dataset/schema markers, checksum-linked provenance source, and passing reference validation report, while the H.264 MP4 is explicitly non-authoritative and has zero grading weight. An ordinary CPU-only Linux workflow can load the supplied inputs, run a deterministic Python solution twice through the required shell interface, and have both outputs evaluated offline against the hidden reference. License keys, accounts, tokens, and other credentials are not required from the contributor. Confidential, proprietary, or internal material may be evaluated as submitted evidence without requiring additional disclosure.

**Special Screening:**
None

**Recommended Changes:**
The submission already provides unusually strong schema documentation, provenance, integrity checks, evaluator tests, positive and negative controls, and answer separation. No changes are required.