Release workflow: only a tag with a suffix (v0.2.0-rc1) is a pre-release; v0.1.1 notes no longer say pre-release

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/release-notes.md

@@ -1,7 +1,6 @@
 SolveCraft is an open-source parametric 3D CAD application in pure Rust: sketch on a plane,
 constrain and dimension the sketch, turn profiles into solids on a feature timeline, and change a
-parameter to watch the timeline rebuild. This is a **pre-release**: it is early, and we'd like
-your bug reports.
+parameter to watch the timeline rebuild. It is early, and we'd like your bug reports.
 
 ## Fixed since v0.1.0