Skill groups — separate/combined round generation

[javaisbetterthanpython]

Summary

Upstream: pickleball-shuffler#25 (part 3 of 3)

Round generation for separate vs combined group play, including swing-player placement and edge-case handling.

Separate groups (default)

• Each group runs an independent jumble schedule.
• UI shows both under the same Round N timeline (Skill groups — court-to-group mapping + rounds layout #34 layout).
• Each group uses its own court count (from court assignments in Skill groups — court-to-group mapping + rounds layout #34).
• Sit-out logic runs per group; UI remains seamless (one sit-out flow, backend per group).

Combined rounds

• Merge all players into one pool — skill labels ignored for that round.
• Courts used = sum of all group court counts.
• Host chooses combined mode per round (override session default from Skill groups — foundation (data model + UI) #33).
• Group court labels hidden on combined rounds (Skill groups — court-to-group mapping + rounds layout #34).

Swing players (multi-group membership)

• Each separate round, swing players assigned to one group by the algorithm to preserve even mix.
• Edge cases / oddities → assign to higher-priority group (drag order from Skill groups — foundation (data model + UI) #33).
• Non-swing players stay in their sole group.

Too-small group

• If a group cannot generate (e.g. <4 players for its court count): block with message.
• Offer host option to switch to combined round to continue.

Mid-session enable

• Enabling groups mid-session (Skill groups — foundation (data model + UI) #33): applies from next round; everyone defaults Standard until reassigned.

Acceptance criteria

• Separate mode: independent schedules per group, shared round numbers
• Combined mode: merged pool, courts = sum of group courts
• Per-round separate/combined override
• Swing player assignment per separate round; higher-priority fallback
• Too-small group blocks + offers combined fallback
• Per-group sit-out logic (seamless UI)
• Integrates with Richer session mix + instant next round #30 diversity rules and Skill groups — court-to-group mapping + rounds layout #34 court layout
• Automated tests for separate/combined/swing scenarios
• yarn test:ci and yarn build pass

Files likely touched

• src/matching/heuristics.ts
• src/matching/worker.ts
• src/useShuffler.tsx
• src/SitoutsModal.tsx
• pages/rounds.tsx
• test/heuristics.spec.tsx

Dependencies

• Skill groups — foundation (data model + UI) #33 (groups foundation)
• Skill groups — court-to-group mapping + rounds layout #34 (court-to-group mapping + layout)
• Richer session mix + instant next round #30 (session mix algorithm + pre-gen)

Upstream reference

• Run multiple groups at once panathea/pickleball-shuffler#25