Health survives a door, and experience needs you to be there

Arriving anywhere set health to maximum, so a run cost nothing: walk in,
take what you could, walk out, walk back in whole. Current health now
lives on the character record for the same reason the inventory does --
SimWorld builds a blank player on every instance change, so anything that
must survive a door has to be written down -- and it is banked at every
transfer, every disconnect, and on every item transaction, since a potion
moves an item and hit points in one action.

The hub is where that damage is paid off, at 10% of maximum per second:
about ten seconds from nothing, fast enough not to be a chore and slow
enough to be a decision before walking back in. The dungeon rate is
unchanged, so waiting one out is still not a plan. Regeneration is a
property of the world now rather than a constant.

adopt() no longer touches current health. It is called mid-session by
on_choose_upgrade, and reading health from the record there would snap a
player back to whatever was last written to disk; recompute_max_hp still
clamps downwards so Glass Cannon takes the hit points above the new
ceiling with it. ServerRuntime._adopt_character stays the one place a
record becomes a live player.

Experience is still undivided, but now only among players within
XP_AWARD_RADIUS of the kill -- ten percent past what a player can see, so
anyone who watched it die is inside and someone parked in the entrance
room is not. The death events carry a position for this, and deliberately
do not put it on the wire: encode_events still writes the id alone.

diag_progression covers the whole chain end to end -- wounded in a
dungeon, escaped to the hub with the wound intact, healing there, and
walking back in still hurt -- because a unit test cannot transfer a peer.
Both halves were mutation-tested against it; the unit suite alone missed
the arrival heal entirely.

The Proving Grounds is recorded in the roadmap as a debugging tool that
does not ship: it pays full experience for a boss with 8% health.

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

tests/unit/test_regen.gd

@@ -96,3 +96,50 @@ func test_it_cannot_outpace_incoming_fire() -> void:
 			SimConfig.TEAM_ENEMY, SimConfig.KIND_ORB)
 		world.step()
 	assert_lt(p.hp, start, "standing in fire must still lose health")
+
+
+# --- Where you are decides how fast you heal ---------------------------------
+# Arriving anywhere used to set health to maximum, which made a run free: walk
+# in, take what you can, walk out, walk back in whole. The hub pays that off
+# over about ten seconds instead.
+
+func test_the_hub_heals_far_faster_than_a_dungeon() -> void:
+	var hub := Instance.make_lobby(1)
+	assert_eq(hub.world.regen_percent_per_sec,
+		SimConfig.LOBBY_HP_REGEN_PERCENT_PER_SEC)
+	var run := Instance.make_dungeon(2, 99)
+	assert_eq(run.world.regen_percent_per_sec, SimConfig.HP_REGEN_PERCENT_PER_SEC)
+	assert_gt(hub.world.regen_percent_per_sec, run.world.regen_percent_per_sec,
+		"recovering is what the hub is for; a dungeon must not be a rest stop")
+
+
+func test_a_full_bar_takes_about_ten_seconds_in_the_hub() -> void:
+	var hub := Instance.make_lobby(1)
+	var p := hub.world.add_player(1, "hurt")
+	p.hp = 1
+	for _t in SimConfig.TICK_RATE * 10:
+		hub.step()
+	assert_eq(p.hp, p.max_hp, "ten seconds of standing in the hub is a full bar")
+
+
+func test_the_hub_still_takes_a_noticeable_moment() -> void:
+	# Fast, but not the instant heal this replaced: half a second must not do it.
+	var hub := Instance.make_lobby(1)
+	var p := hub.world.add_player(1, "hurt")
+	p.hp = 1
+	for _t in SimConfig.TICK_RATE / 2:
+		hub.step()
+	assert_lt(p.hp, p.max_hp, "arriving in the hub is not a heal button")
+	assert_gt(p.hp, 1, "but it is visibly happening")
+
+
+func test_a_dungeon_cannot_be_waited_out() -> void:
+	var run := Instance.make_dungeon(2, 99)
+	var p := run.world.add_player(1, "hurt")
+	p.hp = 1
+	p.spawn_grace = 0
+	var before := p.hp
+	for _t in SimConfig.TICK_RATE * 10:
+		p.regenerate(run.world.regen_percent_per_sec)
+	assert_lt(p.hp - before, p.max_hp / 10,
+		"ten seconds in a dungeon must not undo a fight")