PC controls: keyboard pan/zoom, Tab cycle, Escape stack, right-click deselect

Adds full PC keyboard+mouse support on top of existing touch controls. Touch
paths untouched. All input goes through named actions in project.godot.

Bindings:
- WASD / arrows: camera pan (speed scales with zoom)
- = / -: keyboard zoom in/out
- C / Home: center on selected pawn
- Tab / Shift+Tab: cycle through pawns (pans camera to selection)
- B / L / P / ,: toggle BuildDrawer / AlertsLog / WorkPriorityMatrix / Settings
- Escape: cancel active designation tool > close topmost panel > deselect pawn
- Right-click: cancel active tool or deselect pawn (RTS convention)
- F: speed_cycle (action restored; handler still TODO)
- pawn_prev action removed; Shift+Tab read via event.shift_pressed inline

Escape priority enforced by Designation._input running before _unhandled_input
plus each panel consuming its own cancel action when visible.

Also fixes a pre-existing pre-Phase-17 bug: WorkPriorityMatrix, AlertsLog,
StorytellerModal, LoadMenu, and SettingsMenu had MOUSE_FILTER_STOP Controls
(Backdrop / Dim) that remained input-active when the panel was "closed" —
their open/close paths only toggled _root.visible / _panel.visible, never
CanvasLayer.visible. World mouse events (right-click deselect, left-click
pawn-select) were silently eaten. Now each _set_visible / open / close
toggles self.visible (the CanvasLayer) so input dispatch shuts off properly.

Verified end-to-end via MCP runtime: WASD pan, zoom keys, Tab+Shift+Tab
cycle, B-open + Escape-close, right-click deselect, left-click pawn-select
all working in sequence with no input bleed.

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

scenes/world/selection.gd

@@ -14,6 +14,7 @@ const CLICK_MAX_DURATION_MS: int = 300
 
 var _pathfinder: Pathfinder = null
 var _selected_pawn: Pawn = null
+var _camera = null  # Camera2D (CameraRig) — set via bind_camera(); duck-typed to avoid circular preload
 
 # When Designation paint mode is active this flag is raised by Designation so
 # Selection does not also try to select/move on the same click.
@@ -29,13 +30,57 @@ func bind(pathfinder: Pathfinder) -> void:
 	_pathfinder = pathfinder
 
 
+## Inject the CameraRig so Tab-cycle and center-on-selection can pan to the
+## selected pawn's tile.  Call from world.gd after selection.bind().
+func bind_camera(rig) -> void:
+	_camera = rig
+
+
 func selected() -> Pawn:
 	return _selected_pawn
 
 
 func _unhandled_input(event: InputEvent) -> void:
+	# ── Keyboard: Tab → cycle pawns (Shift+Tab reverses) ───────────────────────
+	if event.is_action_pressed("pawn_next"):
+		# Read shift from the event itself (set by the OS on the key event); more
+		# reliable than Input.is_key_pressed(KEY_SHIFT) which doesn't reflect modifier
+		# state from synthetic input events (MCP test injections).
+		var reverse: bool = event is InputEventKey and event.shift_pressed
+		_cycle_pawn(-1 if reverse else 1)
+		get_viewport().set_input_as_handled()
+		return
+
+	# ── Keyboard: C / Home → center camera on selected pawn ─────────────────────
+	if event.is_action_pressed("center_on_selection"):
+		if _selected_pawn != null and _camera != null:
+			_camera.pan_to_tile(_selected_pawn.tile)
+			Audit.log("selection", "center_on_selection → %s" % _selected_pawn.tile)
+		get_viewport().set_input_as_handled()
+		return
+
+	# ── Keyboard: Escape → deselect (lowest-priority; consumed last) ─────────────
+	# Designation._input handles Escape first; panels handle it in _unhandled_input
+	# before reaching here.  If we still see it and have a selection, consume it.
+	if event.is_action_pressed("cancel") and _selected_pawn != null:
+		_deselect()
+		get_viewport().set_input_as_handled()
+		Audit.log("selection", "escape: deselected")
+		return
+
+	# ── Mouse: only handle button events below ───────────────────────────────────
 	if not (event is InputEventMouseButton):
 		return
+
+	# ── Right-click: cancel designation (if active) or deselect pawn ─────────────
+	if event.button_index == MOUSE_BUTTON_RIGHT and event.pressed:
+		# Designation cancellation is handled by Designation._input; if we see
+		# this right-click, no designation was active.  Deselect any selected pawn.
+		if _selected_pawn != null:
+			_deselect()
+			get_viewport().set_input_as_handled()
+		return
+
 	if event.button_index != MOUSE_BUTTON_LEFT:
 		return
 	# Designation paint mode owns input while active; Selection steps aside.
@@ -102,3 +147,36 @@ func _select(pawn: Pawn) -> void:
 	pawn.set_selected(true)
 	EventBus.pawn_selected.emit(pawn)
 	Audit.log("selection", "selected %s at %s" % [pawn.pawn_name, pawn.tile])
+
+
+## Clear the current selection without selecting another pawn.
+func _deselect() -> void:
+	if _selected_pawn == null:
+		return
+	_selected_pawn.set_selected(false)
+	EventBus.pawn_deselected.emit()
+	Audit.log("selection", "deselected %s" % _selected_pawn.pawn_name)
+	_selected_pawn = null
+
+
+## Cycle the selection forward (dir=1) or backward (dir=-1) through World.pawns.
+## Wraps around.  If no pawn currently selected, picks World.pawns[0].
+## Pans the camera to the newly selected pawn's tile.
+func _cycle_pawn(dir: int) -> void:
+	var pawns: Array = World.pawns
+	if pawns.is_empty():
+		return
+	var next_pawn: Pawn
+	if _selected_pawn == null:
+		next_pawn = pawns[0]
+	else:
+		var idx: int = pawns.find(_selected_pawn)
+		if idx == -1:
+			next_pawn = pawns[0]
+		else:
+			idx = posmod(idx + dir, pawns.size())
+			next_pawn = pawns[idx]
+	_select(next_pawn)
+	if _camera != null:
+		_camera.pan_to_tile(next_pawn.tile)
+	Audit.log("selection", "pawn_cycle dir=%d → %s" % [dir, next_pawn.pawn_name])