Characterize live-row and physical-slot reserve compatibility

[RossRichardson]

PR2195 already separates arbitrary live input from private work and calls its lcm-based layout an overreserve. This package makes the resulting interface boundary explicit: under the complete live-packet contract, B = WNH supplies the depth reserve B^D, but an unchanged physical-slot format accepts t B^D exactly when (P/gcd(P,W))^D divides t. For W=28416, P=28425, that gate is 9475^D | t. The historical K_lcm^D remains the minimum positive reserve compatible with both fixed formats.

The contribution is a credited conditional corollary, a complete-row codec, a written all-depth proof, an independent mathematical and symbolic-payload review, and defect-sensitive replay. It preserves all arbitrary input rows, high fibers, private work and parking charges. It does not implement a full selected caller or paid format adapter, change the selected invoice, or establish a new kappa. Minimality is only within the stated complete Cartesian formats.

Sources are pinned to Jose Manuel's PR2195 at 3a1cf78a1ba6322129e42d80c50d21765524d612 and PR2234 at d047ef86fbc5b1614d3d8e2b8d3441413beab73f; six source files are preserved with SHA256/Git-blob checks, original notices and attribution. Prepared for Ross Richardson with substantial OpenAI Codex assistance, including a separate recursive-interface specialist. Independent agent review is not human or formal-kernel review.

Validation at this head:

• Python 3.12 registered package replay passes: 54,840 primary codec rows, 73,710 exact compatibility equivalences, 12 semantic/domain controls, and nine public-CLI test groups including normal/optimized execution, read-only Git-free replay, source/receipt corruption and actual restoration-guard removal.
• Independent replay passes normally and optimized: 148,929 complete rows, 24,192 distinct symbolic payloads, 18,000 compatibility equivalences, and 720 direct minimum-common-reserve searches; its finite domains differ from the primary checker.
• make selected-record-check passes. The selected construction and its records are unchanged; its complete cold replay is outside this package's scope. Hosted CI is not claimed.

Canonical investigation: Discussion2179 claim. The next step is to identify an actual downstream consumer and determine whether it needs the physical-slot format before substituting the smaller divisor. TASK.json records the scoped departure from the stock-envelope card and the overlap limitations.