[Vally] Collect Vally issues encountered by Cloud Apps & Tools team

## Purpose

A shared, living list of **Vally** (and related `microsoft/evaluate`) issues our team has encountered — created so we have one clear place to track them and bring a consolidated picture to the Vally team.

We first ran into these while adopting Vally for the **TypeSpec Authoring** skill/benchmark, but most are likely **not specific to our skill** — we just hit them earlier because of the benchmark's scale and its use of some of Vally's more advanced features.

## How to contribute 🙏

- **If you've hit something similar**, please 👍 or comment on the linked upstream issue
- **If you've already filed your own Vally/evaluate issues**, link them so we can consolidate rather than duplicate.

## Vally / evaluate issues

- [x] https://github.com/microsoft/evaluate/issues/283
- [x] https://github.com/microsoft/vally/issues/427
- [ ] https://github.com/microsoft/evaluate/issues/401
- [ ] https://github.com/microsoft/evaluate/issues/350
- [ ] https://github.com/microsoft/evaluate/issues/282
- [ ] https://github.com/microsoft/evaluate/issues/356
- [ ] https://github.com/microsoft/evaluate/issues/368
- [ ] https://github.com/microsoft/vally/issues/481
- [ ] https://github.com/microsoft/evaluate/issues/338
- [ ] https://github.com/microsoft/evaluate/issues/355
- [x] https://github.com/microsoft/vally/issues/668

_Related: #14667_

Review the checklist of linked microsoft/evaluate and microsoft/vally issues, starting with the unchecked entries and related issue #14667. Done means keeping this shared list consolidated with relevant upstream links and current statuses, rather than implementing a specific code change.

Written by the indexing model from the issue text.