Add Golf game variant with nine-hole match play

[austin-smith]

What Changed

• New Golf variant: seven face-up columns of five, play any exposed card one rank up or down onto the waste (suits ignored), single 16-card stock pass with no recycles. Strict classic rules: no Ace↔King wraparound, and nothing plays on a King.
• Traditional golf scoring, lower is better: the hole score is the cards left on the board; clearing the board subtracts one point per leftover stock card, so negative scores are the best results. Holes roll up into a nine-hole match (par 45) with a scorecard summary, hole-complete interstitials, and a running match total in the header. The floor-0 score clamp, win time bonus, and high-score statistics are all variant-aware so lower-is-better works end to end (best hole, best match, matches completed).
• Solver-backed hints: GolfPlanner runs an exact plays-first depth-first search over a collision-free 30-bit packed position (12-byte search nodes make the 1M-node budget affordable). Winning lines when a deal is winnable, exact max-clear lines when it is not, silence only when nothing is clearable.
• Match lifecycle correctness: the match persists atomically with its board in the save payload and survives game switching via the per-mode session stash; undo can never cross a hole boundary; a dead hole freezes the clock until the player advances (undo resumes without counting overlay dwell); a completed match archives its final board — undo and redeal are gated at the model and in every affordance (toolbar, macOS menu, keyboard); statistics resets revoke a mid-match scorecard's eligibility without erasing it.
• Integration surface: game picker mini-board art, per-game statistics detail with golf-specific rows, rules & scoring in-app copy, hint-probe wiring with recorded ledger baselines, screenshot fixture, README row, and docs/solitaire-rules-golf.md.
• Docs: all seven rules docs now share one section skeleton; Klondike, FreeCell, and Yukon gain the Scoring sections they were missing; solver/baseline content moves out of rules docs entirely (the hint-probe ledger is the single source for those figures).

Why

Golf is the simpler ancestor of TriPeaks — same match-against-the-waste play with a fully open columnar layout — and the lowest-effort addition to that family. Strict rules and traditional match scoring were chosen deliberately: they are the classic game, and the scoring gives lost deals (the majority under strict rules) a meaningful outcome to optimize.

Closes #46

Validation

• Full unit suite: 397 tests, 0 failures (macOS Debug, the CI invocation), including 80+ new Golf tests across rules, session, planner, persistence, match lifecycle, and statistics.
• Hint-probe ledger baseline recorded and reproduced deterministically: 22.6% follower win rate vs 0.0% random control over 500 seeded deals, zero stalemate loops, median 33/35 cards cleared on lost deals (control: 11). Verdict sweep: 26.1% proved winnable / 66.3% proved unwinnable / 7.6% undecided over 10,000 deals.
• iOS and macOS builds clean; exercised end to end in the simulator: deal, tap/drag play, undo, stock, hole-over interstitial (frozen clock, dwell-free undo resume), match advance, kill/relaunch persistence mid-hole and at the summary, game-picker selection, and VoiceOver reachability of the overlay controls.

UI Changes

• Golf board (shared tableau layout) with stock + waste top row.
• Header shows "Hole n/9" on the score tile plus a live Match total tile for Golf.
• Hole-complete and match-summary overlays (modal to VoiceOver, matching the win overlay's chrome).
• Golf mini-board in the game picker gallery.