Adv 2.0 D&D polish: GM→DM rename, streamed zone combat, end-to-end scenario test

GM→DM rename across docs and code (GMNarrationType→DMNarrationType,
GMState→DMState, narration constants, comments) so the system reads as
"Dungeon Master" everywhere. Player-visible "GM mood" wording stays
where it appears in flavor.

Streamed zone/expedition combat: zone advance now stages patrol →
patrol play-by-play → patrol resolution → room intro → room play-by-play
→ final outcome through sendZoneCombatMessages with 2–3s pacing
(arena keeps its 5–8s window). Combat narrative lines pick up a compact
d20-vs-AC roll annotation for hit/crit/miss/block events.

Combat outcome polish: dndHPSnapshot lets narration show sheet HP
rather than legacy combat-engine HP, and markAdventureDead clears the
zombie state where hp_current was 0 but the legacy alive flag stayed
true after a D&D-layer KO.

Adv 2.0 announcement (ADVENTURE_2.0_ANNOUNCEMENT.md), README rewrite
covering the new layer, and adv2_scenario_test.go — a full
zone-run + expedition + harvest playthrough against a copy of the prod
DB asserting persisted state end-to-end.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/dnd.go

@@ -57,7 +57,7 @@ type DnDClassInfo struct {
 }
 
 var dndRaces = []DnDRaceInfo{
-	{RaceHuman, "Human", [6]int{0, 0, 0, 0, 0, 0}, "Versatile (floating +1 bonus deferred to Phase 2)"},
+	{RaceHuman, "Human", [6]int{0, 0, 0, 0, 0, 0}, "Versatile (floating +1 bonus not yet implemented)"},
 	{RaceElf, "Elf", [6]int{0, 2, -1, 1, 1, 0}, "Darkvision; immune to sleep effects"},
 	{RaceDwarf, "Dwarf", [6]int{1, -1, 2, 0, 1, -1}, "Poison resistance; bonus vs. underground enemies"},
 	{RaceHalfling, "Halfling", [6]int{0, 2, 0, 0, 1, 0}, "Lucky: once per combat, reroll a natural 1"},