pins: upstream moved past the lockstep pin set

[github-actions]

Weekly pin watch found upstream movement:

• NVlabs/cuda-oxide HEAD is b22efa99, pin is 50d07314
• vyncint/reconverge latest tag is v0.3.0, pin is v0.1.11

Policy (CONTRIBUTING.md): the nightly, cuda-oxide, and reconverge pins move together or not at all. A bump is its own commit with its own gate re-run, touching EVERY site: rust-toolchain.toml, .github/workflows/pins.yml (env), .github/workflows/prune.yml (env), action/action.yml (input defaults), action/README.md, and CONTRIBUTING.md. This workflow never bumps — a human decides.

[vyncint]

Half of this is now done, and the half that is left is the harder half.

reconverge: the pin was already 0.3.0 when this issue was filed — it read 0.1.11 because action/README.md's input table was two releases stale, which is fixed in 2.0.0. The pin is now 0.4.0, moved in all four places (prune.yml, action.yml, action/README.md, docs/LIMITATIONS.md) with the gate re-run: six corpus kernels, verdicts unchanged, and the new RC004 capability verified reaching matmul-tiled (TM = TK = 128 now reports 73728 bytes over the cap; 0.3.0 reported nothing).

cuda-oxide: still pinned at 50d07314, still behind b22efa99. Untouched deliberately — CONTRIBUTING says the nightly, cuda-oxide and reconverge pins move together or not at all, and a cuda-oxide bump is its own change with its own gate re-run. reconverge 0.4.0 needs the same nightly-2026-04-03, so no toolchain move was required for this one.

Leaving this open for the cuda-oxide half.