Bump source to 0.9.2 and renumber the 0.x roadmap

- Set project.godot to 0.9.2 and add the matching changelog entry.
- Renumber the postponed work to 0.9.3 UI, 0.9.4 NPC, 0.9.5 textures and 0.9.6 integration, with 0.10.0 as the next minor release candidate.
- Remove the 1.0.0 milestone and post-1.0 planning; plan only 0.x patch/minor increments.
- Synchronize README, PLAN, architecture, status, memory and UI-copy version references.

docs/joke-shop-map.md

@@ -75,7 +75,7 @@ just as with the Hollywood day/night rows.
 - The concept frames are photoreal; the game keeps its stylized, low-poly
   material treatment. The vision judge therefore still scores material and
   foliage detail below the reference. The remaining texture/realism work is
-  tracked with the postponed 0.9.4 pass, not treated as a map-geometry defect.
+  tracked with the postponed 0.9.5 pass, not treated as a map-geometry defect.
 
 ## References