Port DeepLinkParsers from 7.x

**Source**: Microsoft.Toolkit.Uwp.UI.Helpers (7.x)
**Destination**: CommunityToolkit.WinUI.Helpers (8.x) — not yet ported

## Description

Provides a way to create, from `IActivatedEventArgs` a `Dictionary`-inheriting object that provides an additional `.Root` property to pull the base path of the URI (eg: in `MainPage/Options?option1=value1`, `.Root` would be `MainPage/Options`).

## Prerequisites

None identified.

## Porting Basics

- [ ] Namespace updated to `CommunityToolkit.WinUI.*`
- [ ] Code for UWP, WinUI3 and Uno Platform consolidated
- [ ] Desired MultiTargets configured
- [ ] Sample code migrated
- [ ] Concept docs migrated
- [ ] Tests migrated and passing

## Quality Evaluation

See [Porting Criteria](https://github.com/CommunityToolkit/Windows/wiki/Component-Quality-Evaluation) for detailed evaluation guidance.

- [n/a] UX: Accessibility reviewed
- [n/a] UX: Visual design reviewed
- [n/a] UX: Interaction patterns appropriate
- [ ] DX: API surface reviewed
- [ ] DX: API flexibility appropriate
- [ ] DX: Documentation updated
- [ ] MX: Breaking changes documented
- [ ] MX: Domain isolation appropriate
- [ ] MX: Test coverage adequate

## Tracking Gaps

*No gaps identified — porting work not yet started.*

## Closing

- [ ] All Porting Basics complete
- [ ] Quality Evaluation reviewed
- [ ] Gaps filed as sub-issues

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## 7x Documentation Inventory

**Docs ported to 8x**: n/a

**Docs not in 8x**:
- Properties
- Methods
- Example
- CollectionFormingDeepLinkParser
- Example
- QueryParameterCollection
- Example
- Output

## 7x Source Inventory

**Source already ported to 8x**: n/a

**Source not ported to 8x**: n/a

## Notes

- Not currently planned for porting. Open to community interest.
- **Archive redirect**: https://learn.microsoft.com/en-us/dotnet/communitytoolkit/windows/archive/deeplinkparsers

Start with the archived DeepLinkParsers documentation and the Microsoft.Toolkit.Uwp.UI.Helpers 7.x implementation, then inspect the CommunityToolkit.WinUI.Helpers 8.x structure. Port the API across the required UWP, WinUI 3, and Uno Platform targets, migrate the sample and concept documentation, and add migrated tests that pass.

Vom Indexierungsmodell aus dem Issue-Text verfasst.