fix(ci): address PR #31 review — harden cross-encoder fixture pipeline

- Fail on encode errors instead of silently writing empty .msgpack files
- Fail test on missing/empty fixture dir instead of silent skip
- Add all missing action variants (MoveSouth, MoveEast, MoveWest,
  Unpause, ToggleStanceDown, WalkAway) to GDScript fixture generator
- Add GDScript fixture staleness check to make pre-pr
- Validate repo root detection before writing outside client/
- Add file.flush() before close in headless mode
- Document fixture failure recovery in DEVOPS.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/tests/gen_client_fixtures.gd

@@ -12,6 +12,7 @@ extends SceneTree
 
 var _Msgpack: GDScript
 var _count := 0
+var _errors := 0
 var _output_dir: String
 
 
@@ -22,27 +23,48 @@ func _init():
 func _run():
 	_Msgpack = load("res://addons/messagepack/messagepack.gd")
 
+	# Resolve repo root from Godot project root (client/).
+	# Assumes client/ is one level below repo root — validated below.
 	var project_root := ProjectSettings.globalize_path("res://")
 	var repo_root := project_root.rstrip("/").get_base_dir()
 	_output_dir = repo_root.path_join("server/tests/fixtures/gdscript")
 
+	if not DirAccess.dir_exists_absolute(repo_root.path_join("server")):
+		push_error("Repo root detection failed: %s/server/ does not exist" % repo_root)
+		quit(1)
+		return
+
 	DirAccess.make_dir_recursive_absolute(_output_dir)
 
 	_generate_inputs()
 	_generate_boundary_inputs()
 	_generate_batch()
 
+	if _errors > 0:
+		push_error("FAILED: %d encode errors encountered" % _errors)
+		quit(1)
+		return
+	if _count == 0:
+		push_error("FAILED: no fixtures generated")
+		quit(1)
+		return
 	print("Generated %d GDScript fixtures at %s" % [_count, _output_dir])
 	quit()
 
 
 func _write_fixture(name: String, bytes: PackedByteArray) -> void:
+	if bytes.is_empty():
+		push_error("Encode produced empty bytes for fixture: %s" % name)
+		_errors += 1
+		return
 	var path := _output_dir.path_join(name + ".msgpack")
 	var file := FileAccess.open(path, FileAccess.WRITE)
 	if file == null:
 		push_error("Failed to write fixture: %s (error: %d)" % [path, FileAccess.get_open_error()])
+		_errors += 1
 		return
 	file.store_buffer(bytes)
+	file.flush()
 	file.close()
 	print("  Wrote %s (%d bytes)" % [name, bytes.size()])
 	_count += 1
@@ -90,10 +112,11 @@ func _encode_inputs(inputs: Array) -> PackedByteArray:
 
 
 func _generate_inputs() -> void:
-	# Unit variants: movement directions (tick=100)
-	_write_fixture("input_move_north",
-		_encode_input(100, "MoveNorth"))
-	for dir_name in ["MoveNortheast", "MoveSoutheast", "MoveSouthwest", "MoveNorthwest"]:
+	# Unit variants: all 8 movement directions (tick=100)
+	for dir_name in [
+		"MoveNorth", "MoveSouth", "MoveEast", "MoveWest",
+		"MoveNortheast", "MoveSoutheast", "MoveSouthwest", "MoveNorthwest",
+	]:
 		_write_fixture("input_%s" % dir_name.to_snake_case(),
 			_encode_input(100, dir_name))
 
@@ -108,8 +131,14 @@ func _generate_inputs() -> void:
 	# Other unit variants
 	_write_fixture("input_pause",
 		_encode_input(100, "Pause"))
+	_write_fixture("input_unpause",
+		_encode_input(100, "Unpause"))
 	_write_fixture("input_toggle_stance_up",
 		_encode_input(100, "ToggleStanceUp"))
+	_write_fixture("input_toggle_stance_down",
+		_encode_input(100, "ToggleStanceDown"))
+	_write_fixture("input_walk_away",
+		_encode_input(100, "WalkAway"))
 
 
 func _generate_boundary_inputs() -> void: