[Server] Add per-run configuration overrides (#7820)

Add --set key=value to override a section-qualified scalar configuration key for a single run and --print-config to print the effective configuration, with secrets redacted. SettingsCache owns the override map, so reads see the override without rewriting the ini file, and rebuilds the disallowed-name regexps when users/disallowedregexp is overridden. Bare keys and array-scoped keys are rejected because array loops read them relative to the active group, where a full-key override would either be ignored or rewrite every entry.

Cover the ini, default, override, override-only-key, regexp-rebuild, secret-redaction, and parse paths with a server-labelled gtest.

tests/settings/CMakeLists.txt

@@ -14,3 +14,15 @@ cockatrice_add_test(
 )
 
 cockatrice_add_test(NAME settings_migration_test SOURCES settings_migration_test.cpp LIBS libcockatrice_settings)
+
+cockatrice_add_test(
+  NAME
+  servatrice_settings_test
+  SOURCES
+  ${CMAKE_SOURCE_DIR}/servatrice/src/settingscache.cpp
+  servatrice_settings_test.cpp
+  INCLUDE_DIRS
+  ${CMAKE_SOURCE_DIR}/servatrice/src
+  LABELS
+  server
+)