fix(studio): render game's odd-R hex geometry for both tile spaces and retune tile border to graphite

[mateicanavra]

Both tile spaces (tile.hexOddR and tile.hexOddQ) now render the game's actual plot geometry: regular pointy-top hexes on a row-offset (odd-R) lattice, with columns √3·size apart, rows 1.5·size apart, and odd rows shifted east by half a tile.

The previous renderer treated tile.hexOddQ as a genuine column-offset lattice and drew a custom squashed flat-top hexagon to tile it exactly. A hex-convention audit (research/03-hex-convention-audit.md) established that Civ7's grid is odd-R, not odd-Q — Firaxis's own debug dumpers indent odd rows, the official direction set has E/W neighbors but no N/S (pointy-top adjacency), and the engine boundary writes (x, y) untransposed. mapgen-core's odd-Q projection puts the offset on the wrong axis, producing a lattice that is not a regular hex tiling, which is why the tiling hexagon had to be vertically compressed and the grid looked squished. tile.hexOddQ is now treated as a mislabel of the same game grid. The world frame (√3·width × 1.5·height) is unchanged, so world.xy co-registration is unaffected.

The odd-Q lattice math, its squashed polygon function, and the separate bounds branch for odd-Q are removed. Both tileCenter, tilePoint, and boundsForTileGrid now use the single odd-R path.

Tile border color is changed from mid-luminance slate ([100, 116, 139, 220]) to graphite ([13, 13, 17, 200], #0d0d11 at α200) — one ink in both themes. Borders only appear between filled tiles; unfilled tiles draw nothing. The dark seam recedes into the canvas in dark mode and reads as a crisp graphite grid in light mode without competing with the data palette.

Tests are updated so both tile spaces assert regular pointy-top vertices (unit radius, vertex straight above center) and the row-offset lattice spacing (same-row y, odd-row east shift). The engine-side migration of mapgen-core from odd-Q to odd-R is tracked as a separate task, as it is gameplay-affecting and requires its own regression plan.

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[mateicanavra]

Merge activity

• Jun 12, 8:50 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jun 12, 10:08 PM UTC: Graphite rebased this pull request as part of a merge.
• Jun 12, 10:08 PM UTC: @mateicanavra merged this pull request with Graphite.