feat!: generate typed keys for every neutral resx, with or without a designer

[rent-a-developer]

Refs #34
Part of #29

The build wiring passes MSBuild's resource name (ManifestResourceName, LogicalName, WithCulture) to the generator through the analyzer config file, and each generated Keys class creates its own ResourceManager from it. Also: the pre-release gate removes cached ResXLocalization packages before the package consumers run, and the generator project no longer lists AnalyzerReleases.*.md twice.

BREAKING CHANGE: generated Keys classes carry their own ResourceManager, created from the resource name MSBuild computes, and their keys no longer use the designer's ResourceManager. Files without a designer and dotted neutral files now produce keys classes; RXLGEN002 is removed. Two files that produce the same keys class report RXLGEN004 instead of merging. See docs/guides/migration-2.0.md.

Checklist

Everything under Always applies to every pull request. The rest applies only when its trigger does —
tick it, or leave it and say why in the description. A box that does not apply is not a box to tick.

Always

• pwsh -File scripts/pre-commit-gate.ps1 passes. It runs the public-API reminder, checks line endings,
  style, formatting and member ordering, builds Release and runs the test suites. Use -Fix to have it
  apply the tidying rather than only report it.
• The Release build produces zero warnings. TreatWarningsAsErrors is on, so this also covers style,
  member ordering, trim and public-API diagnostics.
• Branch name follows <type>/issue-<number>-<slug>, or <type>/<slug> when there is no issue — see
  CONTRIBUTING.md.

If the change adds behaviour or fixes a bug

• It is covered by tests.
• CHANGELOG.md has an entry under ## [Unreleased]. Do not bump a version — the version, the
  release date and the tag are the maintainer's, at release time.

If the change touches one UI package

• It is mirrored into the other, or it genuinely does not apply there — see
  CONTRIBUTING.md. The Avalonia and WPF markup
  extensions and converters are deliberate mirrors of each other.

If the change touches resource lookup, the generated keys, or the packaging that carries them

Culture fallback, satellite discovery, the source generator's output, the buildTransitive wiring, or a
dependency version. Nothing is trimmed on the just-in-time compiler, so no other check in this repository
can see the damage a mistake here does to a trimmed application.

• pwsh -File scripts/verify-package-aot.ps1 -Pack passes for both frameworks
  (-Framework net8.0 and the net10.0 default).
• No new IL2xxx / IL3xxx diagnostics, and none suppressed.

If the change touches the public API

• The affected PublicAPI.Unshipped.txt is updated with pwsh -File scripts/update-public-api.ps1, and
  the diff was reviewed line by line. A *REMOVED* entry is a breaking change.
• The XML documentation and the affected pages under docs/ are updated.

[codecov]

Codecov Report

❌ Patch coverage is 93.00000% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...Localization.SourceGenerators/ResxKeysGenerator.cs	93.00%	0 Missing and 7 partials ⚠️

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