VSIX — Health Icon, Namespace Grouping & Loading Indicator (v1.51.0)

Three UX improvements to the ⚡ Flow Catalog sidebar (VSIX v1.2.1+):

Health icon — each method node in the tree now shows a status badge derived from its registry _Info:

Icon	Condition
✅	Has [ResultFlow] diagram + at least one declared error type
⚠️	Has [ResultFlow] diagram but no error types (errors inferred or absent)
❌	No diagram or registry missing

Namespace grouping — classes are now grouped under intermediate namespace nodes (top two segments) between the project root and the class list, keeping large workspaces navigable.

Loading indicator — while dotnet build is running, the affected project node shows a spinning $(loading~spin) icon and "Building…" description; restores to the health/build-status icon on completion.

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