feat(docs): add D-066 dual-scale grid decision and propagate to all docs

0.5m sim tiles for movement/LOS granularity, 1m visual tiles for
proportional art and readable spaces (2x retina factor). All world
geometry constrained to 2x2 sim tile minimum so cover/LOS maps 1:1
with visuals. Entities occupy 1x1 sim tiles for fine positioning.

Updates: D-043, D-044, D-051, D-056, D-059 annotations, workshop
outcomes (art direction + control/interaction), sprint 6 briefings,
decision index, and CLAUDE.md.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/sprints/sprint-6/joint.md

@@ -23,7 +23,7 @@ This sprint emerged from the **Control & Interaction Workshop** (2026-02-13), wh
 
 Two open questions were resolved during the workshop and ticket creation:
 
-- **OQ-01: Tile size** — Resolved to 0.5m x 0.5m (ticket #444, done)
+- **OQ-01: Tile size** — Resolved to 0.5m x 0.5m sim tiles (ticket #444, done). Amended by D-066: dual-scale grid with 1m visual tiles (2x retina factor). All world geometry 2x2 sim tile minimum.
 - **OQ-24: Inventory capacity** — Resolved to 3x3 grid = 9 slots universal (ticket #445, done)
 
 All blocking decisions are confirmed. No pre-sprint work required.

docs/sprints/sprint-6/server.md

@@ -29,7 +29,7 @@ Use `db/connectors/ticket show <id>` for full details.
 
 ## Open Questions Resolved
 
-- **OQ-01: Tile size** — Resolved to 0.5m x 0.5m (ticket #444, done)
+- **OQ-01: Tile size** — Resolved to 0.5m x 0.5m sim tiles (ticket #444, done). Amended by D-066: dual-scale grid with 1m visual tiles (2x retina factor). All world geometry 2x2 sim tile minimum.
 - **OQ-24: Inventory capacity** — Resolved to 3x3 grid = 9 slots universal (ticket #445, done)
 
 ## Notes