Fix ox-hugo export with internal ID links and Quartz config

- Add org-id resolution for [[id:...]] links by building ID locations
  database once before parallel export
- Handle broken file links gracefully with org-export-with-broken-links
- Fix race condition in parallel exports by pre-building ID cache
- Fix Quartz config not being applied: cp was preserving nix store hash
  prefix in filename instead of using explicit destination filename
- Continue pipeline even when some exports fail, reporting failures
- Improve error handling and logging throughout export pipeline

nix/module.nix

@@ -102,8 +102,8 @@ in
         HEALTH_PORT = toString cfg.healthPort;
         ZOTERO_URL = cfg.zoteroUrl;
         CITATION_MODE = cfg.citationMode;
-      } // lib.optionalAttrs (cfg.bibtexFile != null) {
-        BIBTEX_FILE = toString cfg.bibtexFile;
+      } // lib.optionalAttrs (cfg.bibtexFilePath != null) {
+        BIBTEX_FILE = toString cfg.bibtexFilePath;
       };
 
       serviceConfig = {