Fix meta.ini duplicate keys and SKSE Log Redirector mapped folders

meta.ini: Qt6 QSettings IniFormat is case-sensitive on Linux. Pre-existing
CamelCase keys + lowercase setValue() left both casings in the file, so
mods grew duplicate entries on every install. Added MetaIniUtils::
normalizeMetaIniCase() to fold keys to lowercase and dedupe per-section
(keeping non-empty values) before any QSettings open in readMeta,
saveMeta, doInstall, and createMod.

SKSE Log Redirector: deployExternalMappings created per-file symlinks
under the redirected destination, so any new log file the game wrote
post-deploy ended up as a real file outside the mapping. For
isDirectory && createTarget mappings, now publish a single directory
symlink dst -> src when the destination is missing, an existing symlink,
or empty. Falls back to per-file symlinks when dst already has real
content (preserves user data). Cleanup removes the symlink, leaving no
files behind.

Tests under src/tests/ (gtest, opt-in via BUILD_TESTING):
- test_metainiutils: 6 tests covering no-op cases, case-only dedup,
  multi-line continuations, per-section scoping, and end-to-end
  verification that QSettings duplication is fixed.
- test_external_dir_mapping: 6 tests covering directory symlink deploy,
  flow-through writes, idempotency, empty-dir replacement, real-file
  fallback, and cleanup.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b4b1758..71de209 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -285,3 +285,8 @@ endif()
 
 # Main organizer executable
 add_subdirectory(src/src)
+
+if (BUILD_TESTING)
+    enable_testing()
+    add_subdirectory(src/tests)
+endif()