Sprint 46: Add weather forecast hub

[KevinBigham]

Summary

• Adds a /league/weather forecast hub that derives the current forecast slate from existing schedule, team, user-team, and week selectors.
• Adds an 8-variant hand-crafted weather glyph SVG set for sunny, partly cloudy, cloudy, rain, snow, wind, dome, and heat-wave states.
• Covers forecast cards, user/outdoor/dome filters, impact tiers, empty state, glyph variants, and additive route registration with renderToStaticMarkup tests.

Save schema impact

None. SAVE_VERSION remains 35; no engine/save/migration/fixture files changed.

How to test

• NODE_OPTIONS=--no-experimental-webstorage npx --yes pnpm@9.15.9 -r typecheck
• NODE_OPTIONS=--no-experimental-webstorage npx --yes pnpm@9.15.9 test
• NODE_OPTIONS=--no-experimental-webstorage npx --yes pnpm@9.15.9 --filter @mfd/web build
• bash scripts/check-bundle-size.sh
• bash scripts/check-math-random.sh

Look for all commands to pass, index gzip below 181 KB, engine bundle gate unchanged at 257 KB, and no Math.random violations.

Risks / handoff for Claude Code

• No new selector was added; the connected wrapper consumes selectSchedule, selectTeams, selectUserTeam, and selectWeek.
• Engine WeatherCondition currently exposes dome, clear, rain, snow, and wind. The extra glyph variants are available for UI richness, while connected schedule data maps clear outdoor games to sunny or heat-wave profiles.
• Route registration is additive in App.tsx via a new lazy route and post-routeTree addChildren call.
• No packages/engine changes.