Port to ort 2.0.0-rc.12 (ndarray 0.17)

[seanianallen]

Hi! This ports orp to ort 2.0.0-rc.12 / ndarray 0.17, keeping the public API unchanged. Companion PR for gline-rs is open as well.

Why

ort 2.0.0-rc.9 targets ONNX Runtime 1.20.x, which is increasingly hard to pair with current system installs (Homebrew and most distros now ship 1.24+). rc.12 supports ORT 1.17–1.24 via multiversioning, and empirically works against 1.26 with load-dynamic.

What changed (all driven by rc.9 → rc.12 API changes)

• Session::run now requires &mut Session. To preserve this crate's &self inference API (and the Composable trait contracts), Model wraps the session in a Mutex held per inference call — ONNX Runtime parallelizes internally via intra-op threads, so concurrent callers serialize at the run boundary only.
• SessionOutputs lost its second lifetime parameter. It now only borrows the output name strings from the session's outlet metadata (values are owned DynValues); a documented transmute widens that borrow from the mutex-guard region to the model borrow 'a, keeping the PostProcessor<'a, …> trait signatures unchanged.
• Builder option methods return Error<SessionBuilder>, whose recovery payload is neither Send nor Sync; a small helper strips the payload so ? conversion to Box<dyn Error + Send + Sync> keeps working.
• ModelMetadata getters return Option; Session/Outlet fields moved behind accessors (inputs(), outputs(), name()", dtype()`).

Builds clean with --features load-dynamic; exercised end-to-end via the gline-rs test suite (17/17) against ONNX Runtime 1.26.

Happy to adjust anything to your taste — in particular the Mutex vs. exposing &mut inference, if you'd rather break API.

[seanianallen]

Heads-up: ort 2.0.0-rc.13 shipped this week (ONNX Runtime 1.28 baseline). I've validated this port against rc.13 as well — the only deltas are EP compile-time feature-gating and custom-operator API changes, neither of which orp touches, so this branch bumps cleanly. Happy to update the PR to rc.13 directly if you'd prefer to land on the latest rc, or keep it at rc.12 as submitted — whichever is easier to review. An rc.13 branch is ready at seanianallen/orp:ort-rc13 either way.

[fbilhaut]

Hi @seanianallen, sorry for the delay and thank you very much for this very useful contribution.

I think that, while we're at it, and given that rc.13 is considered production ready, it makes sense to move directly to that version.

Note that I will be shortly releasing the current state of orp and related crates so we can start on a clean state, and let people use them if they prefer to keep using rc9.