docs(mapgen-studio): record Pass-5 design fixes (toolbar v2, tile orientation, grid icon, flash guard, pre-run cursor)

[mateicanavra]

Records the completion of Pass-5 design fixes for the mapgen studio redesign, covering five implemented slices:

• Toolbar architecture v2: Top bar restructured as the Game toolbar with a Gamepad2 identity, saved-config selector, inlined GameConsole cluster, and a game-setup disclosure for Leader/Civ/Difficulty/Speed; bottom bar established as the World/Map console with Globe identity, Size/Players/Resources alongside Seed, and a History icon compressing last-run stats
• Grid icon restoration: Fixed a ViewControls grid toggle that was rendering an empty div instead of the Grid3x3 icon, with a categorical sweep confirming no other empty placeholders exist
• Tile orientation correction: Odd-Q tiles were drawing pointy-top on a sheared lattice and now render flat-top on the canonical hex space used by the Delaunay/world.xy layers, with correct transparency and border behavior for noData/non-finite tiles
• Flash fix: Eliminated an unstyled root element during reload (~138ms window) by placing background and color-scheme on :root for both theme branches inline, bringing dark root rendering down to ~8ms
• Pre-run cursor honesty: Canvas is now inert with a default cursor before a manifest exists, replacing a grab cursor that promised an invisible drag; grab/grabbing and the deck controller are restored post-run via setProps without remounting

Also records a new standing rule: search existing component libraries (shadcn/ui first) before building custom UI patterns from scratch. All five slices verified on :5173 with 167 passing tests and five strict OpenSpec validations.

[github-actions]

Railway preview (MapGen Studio): not provisioned for this PR.

Policy (Graphite stacks): previews are created only for the top-of-stack PR by default.

• To force a preview for this PR: add label railway-preview
• To suppress a preview: add label no-railway-preview

Debug: {"isClosed":false,"isFork":false,"suppress":false,"force":false,"isTopOfStack":false,"hasToken":true,"draft":false}

[mateicanavra]

Merge activity

• Jun 12, 8:50 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jun 12, 10:06 PM UTC: Graphite rebased this pull request as part of a merge.
• Jun 12, 10:06 PM UTC: @mateicanavra merged this pull request with Graphite.