Stage 5: bosses that move, attacks that warn, and a second boss

Boss movement is a property of the PHASE, not of the boss -- a fight that
stands still and then starts hunting you is one boss with two phases. Four
modes (STATIC, ORBIT, CHASE, WAYPOINTS) handled generically in
SimWorld._move_boss, so a boss that moves is still data. BossDef.stationary
is gone rather than kept beside the phases: a flag claiming the boss stood
still while a phase walked around would be a second source of truth and the
wrong one, so moves() is derived.

CHASE holds a distance instead of closing, because a boss standing on top of
you is a boss whose bullets cannot be read. Waypoints are fractions of the
arena so one phase works in rooms of different sizes. Every mode is speed
clamped in one place -- ORBIT computes an absolute destination and would
otherwise snap onto its circle on the first tick -- and movement slides
against geometry so a boss cannot walk through the pillars its own arena was
designed around.

The room clamp moved to after movement, where it is finally load-bearing. It
was a no-op while every boss stood still, which is exactly when an invariant
is cheapest to establish: boss rooms deliberately do not lock, so walking out
is always an escape, and that only holds if the boss cannot follow.

TelegraphedStrikeEmitter marks spots and fills them a moment later. The moment
between is the feature: a burst at your feet is a coin flip, the same burst
with a second of notice is a question. It stays stateless like every other
emitter -- they are shared resources and two bosses of the same kind must not
stomp each other -- so strike positions are derived from the volley number and
a test asserts the burst lands where the marker promised. Markers are drawn
through fog and through walls, unlike everything else in the view, because a
warning you cannot see is an unavoidable hit with extra steps.

The Cantor of the Vault fights in the choir vault: static, then a four-corner
circuit, then a chase, then orbiting while marking. It exists to prove the
format stretched, and a test asserts it uses both new mechanisms.

Which boss a run has now comes from its SEED rather than its depth. Depth is a
dev flag nothing in play raises, so the arena was keyed to something no player
can change and the second boss was unreachable in an actual game.

Two things found while finishing:

  - tools/export_content.gd had a hand-maintained boss list and had already
    gone stale, silently not writing the Cantor. Content.ALL_ENEMIES and
    ALL_BOSSES now feed the export tool, the renderer and five tests that each
    kept their own copy.
  - diag_loot failed intermittently after another diagnostic. Taking over from
    the bot cleared its input queue but not its HELD input, so a starved server
    coasted on the bot's last movement vector for half a second and walked the
    player off the item it had been placed on. The press arrived correctly,
    which is why "the press reached the simulation" passed while everything it
    should have caused failed.

check.sh clean, 409 tests, SMOKE PASS (19 assertions), all four diagnostics
green.

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

src/sim/sim_world.gd

@@ -568,11 +568,14 @@ func _step_boss() -> void:
 	var phase := boss.current_phase()
 	if phase == null:
 		return
-	# A boss never leaves its arena. Enforced here rather than left to each
-	# boss's movement code, because boss rooms deliberately do not lock: the
-	# player can always walk out, and the fight only stays a fight if the boss
-	# cannot follow. Currently a no-op (every boss is stationary), which is
-	# exactly when an invariant is cheapest to establish.
+
+	_move_boss(phase)
+
+	# A boss never leaves its arena. Enforced here rather than inside each
+	# movement mode, because boss rooms deliberately do not lock: the player can
+	# always walk out, and the fight only stays a fight if the boss cannot
+	# follow. It was a no-op while every boss stood still, which is exactly when
+	# an invariant is cheapest to establish -- now it is load-bearing.
 	if boss.room.size != Vector2.ZERO:
 		boss.pos = boss.room.position + Vector2(
 			clampf(boss.pos.x - boss.room.position.x, 0.0, boss.room.size.x),
@@ -584,6 +587,72 @@ func _step_boss() -> void:
 	boss.phase_tick += 1
 
 
+## One tick of boss movement, driven entirely by the phase's data. Every mode
+## here is generic: adding a boss that moves is writing a [BossPhase], not
+## touching this function.
+func _move_boss(phase: BossPhase) -> void:
+	if not phase.moves():
+		return
+	var dt := SimConfig.TICK_DELTA
+	var step := Vector2.ZERO
+	match phase.move:
+		BossPhase.Move.ORBIT:
+			var centre := boss.room.get_center() if boss.room.size != Vector2.ZERO \
+				else boss.def.spawn_pos
+			var angle := float(boss.phase_tick) * dt \
+				* (phase.move_speed / maxf(phase.move_param, 1.0))
+			step = centre + Vector2.RIGHT.rotated(angle) * phase.move_param - boss.pos
+		BossPhase.Move.CHASE:
+			var quarry := nearest_player(boss.pos)
+			if quarry == null:
+				return
+			var to_player := quarry.pos - boss.pos
+			var gap := to_player.length()
+			if gap < 0.001:
+				return
+			# Signed, so it backs off when you close inside its preferred
+			# distance. A boss that ends up standing on you is a boss whose
+			# bullets you cannot see coming.
+			step = (to_player / gap) * signf(gap - phase.move_param) * phase.move_speed * dt
+		BossPhase.Move.WAYPOINTS:
+			if phase.waypoints.is_empty():
+				return
+			if boss.waypoint_wait > 0:
+				boss.waypoint_wait -= 1
+				return
+			var goal := _waypoint_world(phase, boss.waypoint_index)
+			var to_goal := goal - boss.pos
+			if to_goal.length() <= phase.move_speed * dt:
+				boss.pos = goal
+				boss.waypoint_index = (boss.waypoint_index + 1) % phase.waypoints.size()
+				boss.waypoint_wait = phase.waypoint_dwell
+				return
+			step = to_goal
+		_:
+			return
+	# Clamped here rather than in each branch, so no mode can teleport: ORBIT in
+	# particular computes an absolute destination and would otherwise snap to
+	# its circle on the first tick of the phase.
+	var reach := phase.move_speed * dt
+	if step.length() > reach:
+		step = step.normalized() * reach
+	# Slid rather than assigned, so a boss cannot walk through the pillars its
+	# own arena was designed around.
+	boss.pos = map.slide_circle(boss.pos, step, boss.def.radius)
+
+
+## A phase waypoint, given as a fraction of the arena, in world coordinates.
+## Fractions rather than absolutes so one phase can be dropped into any room --
+## the Warden's hall and the Choir Vault are different sizes.
+func _waypoint_world(phase: BossPhase, index: int) -> Vector2:
+	var w: Vector2 = phase.waypoints[index]
+	if boss.room.size == Vector2.ZERO:
+		return boss.def.spawn_pos
+	return boss.room.position + Vector2(
+		clampf(w.x, 0.0, 1.0) * boss.room.size.x,
+		clampf(w.y, 0.0, 1.0) * boss.room.size.y)
+
+
 ## Shared emitter driver for enemies and bosses -- the reason a boss pattern can
 ## be dropped onto a trash mob and vice versa.
 func _run_emitters(emitters: Array[BulletEmitter], origin: Vector2, local_tick: int,
@@ -592,6 +661,9 @@ func _run_emitters(emitters: Array[BulletEmitter], origin: Vector2, local_tick:
 		return
 	var target := nearest_player(origin)
 	_ctx.pool = pool
+	# Re-pointed every call: drain_events() replaces the array wholesale, so a
+	# context holding the old one would announce into a list nobody reads.
+	_ctx.events = events
 	_ctx.origin = origin
 	# Curtain patterns span the room they are fired in. Without a room, fall
 	# back to a box around the shooter rather than the whole map, or a trash