<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
This PR replaces the original Mages-based expression evaluation engine
with a WinRT-wrapped version of Exprtk in the CmdPalCalculator module.
### Key Changes
**Expression Engine:**
- All expression parsing and evaluation now use Exprtk (via a WinRT
wrapper) instead of Mages.
**Base Conversion Handling:**
- Since Exprtk does not support non-decimal (binary, octal, hexadecimal)
input natively, added logic to convert all such inputs to decimal before
evaluation.
**Code Structure:**
- The overall logic and API surface remain unchanged except for the
engine and base conversion handling.
- All previous Mages references and dependencies have been removed.
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## PR Checklist
- [ ] **Closes:** #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end user facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx
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## Validation Steps Performed
