Make JasperFx.Events.SourceGenerator flow transitively (drop DevelopmentDependency)

[jeremydmiller]

Problem

Marten 9 removed the runtime evolver fallback, so every project that defines projection types needs this source generator at compile time — including projects that reference only the Marten package.

This package is marked <DevelopmentDependency>true</DevelopmentDependency>, which NuGet consumes as PrivateAssets=all, so the analyzer never flows transitively from a package that references it (notably Marten) to that package's consumers. A consumer referencing only Marten therefore never ran the generator and hit No source-generated dispatcher found ... at DocumentStore.For() (marten#4557).

The workaround in Marten 9.0.2 (marten#4558) was to bundle a copy of this analyzer DLL inside the Marten package (analyzers/dotnet/cs). That fixed plain-Marten consumers but introduced a new failure: any project that also references this package directly now receives the analyzer from two distinct package paths (Marten's bundled copy + this package). Roslyn can't dedup analyzers by content, so AggregateEvolverGenerator runs twice and emits each projection's generated constructor + Evolve/DetermineActionAsync twice — CS0111 "already defines a member". This broke real downstream solutions whose projection-defining projects followed the documented guidance of referencing this package explicitly.

Fix

Drop DevelopmentDependency so the package flows transitively as a normal analyzer-only dependency.

• It has no runtime surface (IncludeBuildOutput=false, no lib/), so flowing it adds nothing to consumers at runtime.
• Because it's a single package identity, a consumer that also references it directly collapses (direct + transitive) to one analyzer path — duplicate generation / CS0111 becomes impossible.

Companion change (separate Marten PR)

Marten should stop bundling the analyzer and instead reference this package with PrivateAssets=none so it flows. That Marten change should target the release that carries this version, and bump Marten's JasperFx.Events.SourceGenerator reference accordingly.

Verification

Built two repro consumers against locally-built packages:

• Marten only → generator flows transitively, evolver generated, clean build (fixes marten#4557).
• Marten + explicit reference to this package → exactly one analyzer path reached csc, one evolver generated, zero CS0111, clean build.

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