Follow the GDScript style guide in every script

- Types on every parameter, return value and variable, and snake_case names
  (the player name limit is the constant MAX_NAME_LENGTH).
- Spelling fixes: *_triggered, character_selected, separator, caught_errors.
  The server's catched_errors key stays as the server sends it.
- Signals are connected with signal.connect() instead of by name.
- Code is ordered signals, constants, exported vars, vars, @onready vars,
  functions, with @onready on one line and two blank lines between functions.
- Every script starts with a ## description. Template comments, old LOC notes
  and commented-out code are gone, apart from the local play code.
- Lines are at most 100 characters, apart from the local play path.
- The screenshot tour turns off the blinking text cursor so pictures match.

tests/integration/test_sync_popup.gd

@@ -1,4 +1,5 @@
 extends GdUnitTestSuite
+## The sync popup on its own: starting a sync, its progress, and how the result is shown.
 
 var _server: FakeHttpTransport
 var _snapshot: AutoloadSnapshot
@@ -132,7 +133,7 @@ func test_errors_are_listed() -> void:
 
 	_finish_sync(result)
 
-	assert_bool(_node("CatchedErrorsVBox").visible).is_true()
+	assert_bool(_node("CaughtErrorsVBox").visible).is_true()
 
 
 func test_reopening_after_sync_shows_result_without_syncing_again() -> void:
@@ -152,7 +153,7 @@ func test_errors_section_has_errors_header() -> void:
 
 	_finish_sync(result)
 
-	assert_str((_node("CatchedErrorsVBox").get_child(0) as Label).text).is_equal("Errors")
+	assert_str((_node("CaughtErrorsVBox").get_child(0) as Label).text).is_equal("Errors")
 
 
 func test_long_names_wrap_instead_of_widening_the_window() -> void:
@@ -173,7 +174,7 @@ func test_long_names_wrap_instead_of_widening_the_window() -> void:
 	var panel_width: float = (_window.get_node("SyncPanel") as Control).size.x
 	assert_float(_node("SyncHBoxContainer").get_combined_minimum_size().x) \
 			.is_less(panel_width)
-	assert_float(_node("CatchedErrorsVBox").get_combined_minimum_size().x) \
+	assert_float(_node("CaughtErrorsVBox").get_combined_minimum_size().x) \
 			.is_less(panel_width)