Integrate native Rime and stabilize input, output, and rendering

- Add optional modifier-only Super binding whose tap is cancelled by
  other input, focus changes, grabs, locks, and session teardown.
- Ship the native ferese-rime user service, Rime defaults, installer
  inventory, package dependencies, session environment, and docs.
- Vendor Smithay 8a27023 with the SHM texture-cache format fix and add
  GPU regressions for format changes and resize snapshots.
- Release reused CRTC owners before staging output modes, then restore
  changed outputs before former owners when a transaction fails.
- Wait for resize-capture GPU completion, expand filtered surface
  damage, and preserve IME popup origin under fractional scaling.
- Mark weekends like holidays in both calendar layouts.

vendor/smithay/.github/pull_request_template.md

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+## Checklist
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+* [ ] I agree to smithay's [Developer Certificate of Origin](https://github.com/Smithay/smithay/blob/master/DCO.md).