Adopt one organic global graph layout

[Chychyndr]

Fixes #120.

Rebuilds the graph around the owner-provided Claude reference model.

Interaction model

• one deterministic global hero layout;
• every published relationship line already exists in Overview;
• desktop Focus keeps the exact Overview camera transform;
• selecting a hero does not move hero coordinates, change portrait footprint, or change edge endpoints;
• Focus only changes emphasis and reveals contextual names, percentages, and HeroCard;
• active relationships remain straight source-to-target SVG lines;
• unrelated heroes remain in place and dim instead of being replaced by a Focus overlay;
• hero-name anchors are deterministic and independent of HeroCard placement;
• win-rate pills stay centered on their own straight relationship segment.

Layout

• deterministic force-directed generation;
• larger organic field with stable committed coordinates;
• no rows/columns, two-sided Focus scaffold, or symmetric selected-hero star;
• all 127 heroes remain part of the same global graph in Overview, Hover, Focus, and Matchup.

Verification

• unit/type/build/design checks pass;
• Playwright verifies that Focus preserves the persistent edge set;
• edge x1/y1/x2/y2 stay unchanged from Overview to Focus;
• portrait radii stay unchanged from Overview to Focus;
• every active edge remains a direct SVG line;
• all-hero audit iterates through all 127 heroes;
• collision audits cover percentages, hero labels, portraits, and direct active links;
• CI screenshot suite captures Overview plus representative Hover/Focus/Matchup/mobile states.

Latest completed code run before the final documentation-only cleanup: 74 unit tests and 56 Playwright tests passed.

Keep this PR unmerged until owner review.