fix(studio): store overflow + visual clutter (v0.31.1)

Two issues from the user feedback after v0.31.0:

1. RenderFlex overflow in the store body. The inner Column
   wrapped the editorial chrome (Today, Recommended,
   Featured) plus an Expanded grid; on small windows the
   chrome alone exceeded the available height and the grid
   got squeezed past zero, painting the yellow-and-black
   stripe.

   Fix: wrap the inner Column in a SingleChildScrollView so
   chrome and grid scroll as one continuous surface
   (App-Store / Play-Store behaviour). The grid switches to
   `shrinkWrap: true` + `NeverScrollableScrollPhysics()` so
   it doesn't try to claim its own viewport.

2. "Der Store ist zu unaufgeräumt, ich fühle mich
   erschlagen." — three editorial cards stacked above the
   filter row + grid was too much.

   Visual cleanup:
   - The recommended-source quick-add chips are now inlined
     into the Today hero's footer (same row as the CTA).
     The standalone `_RecommendedSourcesStrip` only fires in
     the corner case where Today is dismissed AND no
     federation exists yet.
   - The Featured strip no longer competes with Today —
     it only renders once Today has been dismissed. Today
     plays the editorial-hero role; Featured is the
     fallback editorial surface.
   - Provenance pill ("native") is dropped on native cards.
     Native is the default and doesn't earn a badge — only
     foreign code (mcp / n8n) gets the provenance pill, the
     same way "verified" is opt-in in commercial app stores.

Net: at most one editorial card above the grid at any time.
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

pubspec.yaml

@@ -1,7 +1,7 @@
 name: fai_studio
 description: "F∆I Studio — desktop GUI for the F∆I hub"
 publish_to: 'none'
-version: 0.31.0
+version: 0.31.1
 
 environment:
   sdk: ^3.11.0-200.1.beta