fix(theme-guard): close the drift guard's third miss — the meta-guard's own continue whitelisted the gap

test_committed_tres_matches_builder has now been "fixed" three times (traps.md #12).
v1 hardcoded 3 checks; v2 iterated ThemeKeys.ALL but missed the six font roles; v3
added a meta-guard specifically to catch "the builder styles a thing guarded by
nothing" — but that meta-guard contained `if fresh.get_type_variation_base(variation)
== &"": continue`, which whitelisted exactly the case it was built to catch. The
builder styles RichTextLabel directly (build_game_theme.gd's _rich_text()), with no
set_type_variation, so it reports base "" and was skipped unconditionally — and
RichTextLabel is what renders every line of DM prose the creation screen shows
(_origin_text, _detail_blurb). Nothing compared its fonts, font size, or colour, nor
the theme-level default_font/default_font_size, against the committed .tres.

Adds ThemeKeys.BASE_TYPES for base Control types the builder styles directly, folds
it into the drift guard's coverage, replaces the meta-guard's continue with an
assertion that names the offending type, and adds the missing theme-level default
font/size comparison. Proved with three reverted breaks: a RichTextLabel font-size
edit, a theme-level default_font_size edit, and an unregistered "GhostRole" variation
— all three now go red and name the drifted property.

Also: strengthens test_creation_copy's error-copy sweep to assert a mapped error
actually reaches its authored line rather than silently falling through to the
generic UNSPOKEN fallback (CreationCopy.UNSPOKEN satisfied all four prior checks,
so a renamed validator string could regress silently); and removes two assertions
that were true by construction / already true before their test's action ran.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client/tests/unit/test_creation_copy.gd

@@ -141,10 +141,35 @@ func test_an_unmapped_error_still_speaks_in_voice():
 	assert_false(CreationCopy.UNSPOKEN.contains("_"))
 
 
+func _is_deliberately_unmapped(raw: String) -> bool:
+	# The shapes error_line has NO authored line for, on purpose, because the
+	# screen structurally cannot produce them (CreationDraft always emits an
+	# int seed and a spend built only from increment/decrement, which can
+	# never exceed the pool or name a non-attribute) — a malformed seed or
+	# spend, or a broken content reference, is not a player mistake to voice
+	# in character; test_an_unmapped_error_still_speaks_in_voice already pins
+	# the fallback for exactly this set. Named by the validator's own prefixes
+	# so this stays independent of error_line's internals.
+	return (raw.begins_with("unresolved ref:")
+		or raw.begins_with("seed is required")
+		or raw.begins_with("spend")
+		or raw.begins_with("cannot spend on")
+		or raw == "skills must be an array")
+
+
 func test_no_error_the_validator_can_raise_reaches_the_player_raw():
 	# Sweep EVERY error NewGame.validate actually produces for a draft the screen can
 	# be driven into (plus the hostile shapes only a saga could hand it), and assert
-	# the player never sees the id, the underscore, or the validator's grammar.
+	# the player never sees the id, the underscore, or the validator's grammar — AND,
+	# for every shape error_line actually has an authored line for, that the line
+	# fired rather than silently falling through to the generic UNSPOKEN fallback.
+	#
+	# CreationCopy.UNSPOKEN ("something in this does not hold — look again") is
+	# itself non-blank, isn't the raw string, has no underscore, and has no "got " —
+	# so the four checks below cannot tell "correctly mapped to its authored line"
+	# from "silently fell through." Without the UNSPOKEN check, renaming a validator
+	# string in new_game.gd so an error_line branch stops matching would leave every
+	# error line reading the generic fallback, suite green.
 	var d := _draft()
 	var hostiles: Array = [
 		{"name": "", "skills": [], "bonus_skill": ""},               # nameless, unpicked
@@ -165,6 +190,7 @@ func test_no_error_the_validator_can_raise_reaches_the_player_raw():
 	}
 
 	var seen := 0
+	var mapped_seen := 0
 	for h in hostiles:
 		var creation := base.duplicate(true)
 		for k in h:
@@ -173,9 +199,16 @@ func test_no_error_the_validator_can_raise_reaches_the_player_raw():
 		assert_gt(errors.size(), 0, "hostile creation %s must actually be invalid, or it guards nothing" % str(h))
 		for e in errors:
 			seen += 1
-			var line: String = CreationCopy.error_line(str(e), d)
-			assert_ne(line.strip_edges(), "", "'%s' put a BLANK line on the label" % e)
-			assert_ne(line, str(e), "'%s' reached the player raw" % e)
-			assert_false(line.contains("_"), "'%s' put a snake_case id on the label: %s" % [e, line])
-			assert_false(line.contains("got "), "'%s' put the validator's grammar on the label: %s" % [e, line])
+			var raw := str(e)
+			var line: String = CreationCopy.error_line(raw, d)
+			assert_ne(line.strip_edges(), "", "'%s' put a BLANK line on the label" % raw)
+			assert_ne(line, raw, "'%s' reached the player raw" % raw)
+			assert_false(line.contains("_"), "'%s' put a snake_case id on the label: %s" % [raw, line])
+			assert_false(line.contains("got "), "'%s' put the validator's grammar on the label: %s" % [raw, line])
+
+			if not _is_deliberately_unmapped(raw):
+				mapped_seen += 1
+				assert_ne(line, CreationCopy.UNSPOKEN,
+					"'%s' has an authored error_line branch but silently fell through to the generic fallback" % raw)
 	assert_gt(seen, 12, "the sweep must actually reach a spread of errors, not one or two")
+	assert_gt(mapped_seen, 8, "the sweep must actually exercise error_line's mapped branches, not just the deliberately-unmapped ones")