Guardian boss bars; Phase 7 approved

Adrian, 2026-11-03: guardians get a boss health bar like the Wither's, which
also leads players to them. Every player within 128 blocks of a living
guardian sees a red bar of their own (GuardianBars): name, zone, how many
blocks away, and HP. The End boss keeps the dragon's bar.
guardian_appears_and_returns checks the bar appears and goes once beaten.
Self-tests and the island check pass.

Phase 7 approved ("Then begin with the next phase"); README status updated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mod/src/main/kotlin/dev/cobblesurvival/selftest/GuardianTests.kt

@@ -4,6 +4,7 @@ import com.cobblemon.mod.common.battles.BattleBuilder
 import com.cobblemon.mod.common.battles.MoveActionResponse
 import com.cobblemon.mod.common.entity.pokemon.PokemonEntity
 import com.cobblemon.mod.common.util.isInBattle
+import dev.cobblesurvival.zone.GuardianBars
 import dev.cobblesurvival.zone.Guardians
 import dev.cobblesurvival.zone.Zones
 import net.minecraft.core.registries.BuiltInRegistries
@@ -49,6 +50,12 @@ object GuardianTests {
                 s.check(pokemon.isUncatchable()) { "the guardian can be caught" }
                 s.check(abs(pokemon.scaleModifier - definition.scale) < 0.01f) { "the guardian is size ${pokemon.scaleModifier}, not ${definition.scale}" }
                 s.check(expectedLevel == null || pokemon.level == expectedLevel) { "the guardian is level ${pokemon.level}, not $expectedLevel" }
+                // Adrian, 2026-11-03: a boss bar like the Wither's, with how far it is, leads the player to it.
+                GuardianBars.update(level)
+                val bar = GuardianBars.barFor(ZONE, player) ?: throw GameTestAssertException("no boss bar for the guardian 6 blocks away")
+                s.check(player in bar.players && bar.progress == 1f && bar.name.string.contains(pokemon.species.name)) {
+                    "the guardian's bar is wrong: '${bar.name.string}' at ${bar.progress}"
+                }
                 s.moveTo(player, guardian.x + 3, guardian.y, guardian.z)
             }
             .thenWaitUntil { s.check(guardian.pokemon.entity === guardian) { "the guardian has not ticked yet" } }
@@ -65,6 +72,7 @@ object GuardianTests {
             .thenIdle(100)
             .thenExecute {
                 s.check(Guardians.guardianOf(level, ZONE) == null) { "the guardian came back right away" }
+                s.check(GuardianBars.barFor(ZONE, player) == null) { "the beaten guardian's bar is still shown" }
                 Guardians.expireDefeatForTest(level, ZONE)
             }
             .thenWaitUntil {