[Feature Request] Add a winget package for FluentCleaner Classic only

FluentCleaner Classic is not available on winget today. The existing package is the **WinUI 3 / Modern** edition only:

```text
winget search FluentCleaner

Name Id Version Source
-------------------------------------------------------
FluentCleaner Builtbybel.FluentCleaner 26.08.01 winget
```

That package installs `FluentCleaner-win-x64.zip` and depends on `Microsoft.WindowsAppRuntime.2.0`. Please **do not** fold Classic into it. The two editions use different binaries, different runtimes, and different version schemes (`26.08.01` vs Classic `1.15.x`).

## Request

Add a **separate** winget package for **FluentCleaner Classic only**.

Suggested ID (publisher casing already used in winget-pkgs):

```text
Builtbybel.FluentCleaner.Classic
```

Install would look like:

```powershell
winget install Builtbybel.FluentCleaner.Classic
winget upgrade Builtbybel.FluentCleaner.Classic
```

Installer source: the existing Classic zip from GitHub Releases, for example:

- Asset: [`FluentCleaner-Classic-net48.zip`](https://github.com/builtbybel/FluentCleaner/releases/latest/download/FluentCleaner-Classic-net48.zip)
- Nested portable exe: `FCleaner.exe`
- No Windows App Runtime dependency (Classic is .NET Framework 4.8 / WinForms)

Same portable-zip pattern as `Builtbybel.FluentCleaner` is enough. Classic is a much better portable candidate: ~3.5 MB and ~20 files vs ~140 MB / 243 files for Modern.

## Why a dedicated Classic package

- **Tiny and framework-dependent.** Classic runs on machines that already have .NET Framework 4.8. No WASDK install, no 140 MB self-contained bundle.
- **Independent releases.** Classic tags (`classic-1.15.x`) do not move in lockstep with Modern (`26.08.xx`). One winget ID cannot version both correctly.
- **Automation / RMM.** Classic is the edition that is easy to stage on locked-down or older Windows endpoints (`/AUTO`, Task Scheduler, fleet scripts). `winget upgrade` would replace ad-hoc GitHub zip downloads.
- **Avoids fake-site downloads.** Official GitHub is the only source; a first-party winget ID makes that the default install path.

## Out of scope

- No change to `Builtbybel.FluentCleaner` (Modern).
- No request for Chocolatey, Scoop, or an in-app updater in this issue.
- MSI / Inno is nice-to-have, not required. The current Classic zip is sufficient.

Related: #37 (installer / updates; Modern winget is now live), #49 (initial winget-pkgs work for Modern).

Start by reviewing the existing Builtbybel.FluentCleaner winget package pattern and the FluentCleaner-Classic-net48.zip release asset. Verify that the manifest targets FCleaner.exe, the Classic version scheme, and no Windows App Runtime dependency; done means a separate Builtbybel.FluentCleaner.Classic package installs and upgrades from the official GitHub release.

Written by the indexing model from the issue text.