First pass at full refactor to 2.0 design

Restructures the game around the cyclical run loop from Game Design Doc V2:
5 waves = a cycle, 3 cycles = a phase, each phase ends in a boss.

- New TD.Gameplay.Waves: WaveGroup / PhaseDefinition / RunDefinition author the
  run as draggable weighted pools; RunState owns phase/cycle position, the drawn
  wave slots, and the per-slot enemy buff sets. WaveManager's flat wave array is
  gone -- it now only runs the encounter RunState points at.
- New TD.Gameplay.EnemyUpgrades: the post-wave enemy-buff vote, with public
  live-replicated ballots so the HUD can show who voted for what.
- Inter-wave flow is now strictly sequential: draft -> vote -> build, each stage
  ending early once every player has acted.
- Enemy abilities inverted from per-instance random rolls to deterministic,
  stacking per-wave-slot sets. Six cards ship: Split (reworked), Flight, Blink,
  No Bounty, Gold Theft, Double Up.
- Tower upgrades are a two-step tree: a draft pick unlocks a node, gold converts
  an already-placed tower in place.
- Boss encounters flag their enemies and drive a boss HP bar.
- Player cap reduced to 3 via MatchRules.MaxPlayers.
- GoldConfig is now keyed by global encounter number rather than wave index.

Compiles clean; NOT yet verified in-engine. Editor wiring still required --
see Docs/2.0_Setup_Checklist.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assets/_Project/Scripts/Gameplay/GoldConfig.cs

@@ -93,18 +93,26 @@ namespace TD.Gameplay
         [Tooltip("Gold each player starts the match with. Same for every player.")]
         public int StartingGold = 100;
 
-        [Tooltip("Per-wave gold rules. Element 0 = Wave 1. Match the order and length of " +
-                 "WaveManager.waveDefinitions; extra entries are ignored, missing entries " +
-                 "fall back to zero gold for that wave.")]
+        [Tooltip("Per-encounter gold rules. Element 0 = the run's first encounter. Encounters " +
+                 "are counted continuously across the whole run — cycles do NOT restart the " +
+                 "count — so a phase of 5 waves × 3 cycles + a boss needs 16 entries. Missing " +
+                 "entries fall back to zero gold for that encounter.")]
         public WaveGoldEntry[] Waves;
 
         /// <summary>
-        /// Returns the gold entry for the given 1-based wave number, or null if out of range.
+        /// Returns the gold entry for the given 1-based encounter number
+        /// (<c>RunState.GlobalEncounterNumber</c>), or null if out of range.
         /// </summary>
-        public WaveGoldEntry GetWaveEntry(int waveNumber)
+        /// <remarks>
+        /// Keyed by <b>encounter</b>, not by wave slot. Under the cyclical run structure the same
+        /// five waves come round three times per phase, so a slot-keyed table would pay the same
+        /// on cycle 3 as on cycle 1 while the enemies got steadily stronger. A run-long counter
+        /// lets payouts climb monotonically with difficulty.
+        /// </remarks>
+        public WaveGoldEntry GetWaveEntry(int encounterNumber)
         {
             if (Waves == null) return null;
-            int index = waveNumber - 1;
+            int index = encounterNumber - 1;
             if (index < 0 || index >= Waves.Length) return null;
             return Waves[index];
         }