bibliography: setq! for citar, new/import helpers, per-project support

- setq! for citar-bibliography (Doom custom setter, fixes void variable)
- my/bib-new: create new .bib for a project
- my/bib-import-doi: import reference by DOI
- Per-project: .dir-locals.el or #+BIBLIOGRAPHY: in org header
- SPC B prefix (not SPC b which is buffer)

config.el

@@ -1809,28 +1809,31 @@ Skip for beamer exports — beamer uses adjustbox on plain tabular."
 ;;; ============================================================
 ;;; BIBLIOGRAPHY — citar + biblio + org-cite
 ;;; ============================================================
-;; Workflow:
+;; Global .bib: ~/org/references.bib (always available)
-;;   1. SPC b s → search CrossRef/DBLP/arXiv by author/title/DOI
+;; Per-project: add #+BIBLIOGRAPHY: ./refs.bib in org file header
-;;   2. In results: select entry → i = insert into references.bib
-;;   3. In org file: SPC b i → search your .bib → insert [cite:@key]
-;;   4. Export to PDF: citations auto-formatted, bibliography generated
 ;;
-;; Files:
+;; Workflow:
-;;   ~/org/references.bib  — master bibliography (auto-created if missing)
+;;   SPC B n → create new .bib (prompted for path)
-;;   ~/org/notes/           — reading notes per reference
+;;   SPC B s → search CrossRef → in results press 'i' to save to .bib
-;;   ~/org/papers/          — PDF library (optional)
+;;   SPC B i → insert citation in org file
+;;   Export: org-cite + CSL auto-formats references
+;;
+;; Per-project setup: put .dir-locals.el in project root:
+;;   ((org-mode . ((citar-bibliography . ("./refs.bib")))))
 
+;; Global bibliography paths (setq! required for Doom's custom setter)
 (after! citar
-  (setq citar-bibliography '("~/org/references.bib")
+  (setq! citar-bibliography '("~/org/references.bib"))
-        citar-notes-paths '("~/org/notes/")
+  (setq! citar-notes-paths '("~/org/notes/"))
-        citar-library-paths '("~/org/papers/"))
+  (setq! citar-library-paths '("~/org/papers/"))
 
-  ;; Ensure references.bib exists
+  ;; Auto-create global .bib if missing
   (let ((bib (expand-file-name "~/org/references.bib")))
     (unless (file-exists-p bib)
-      (with-temp-file bib (insert "% Bibliography — managed via citar + biblio\n\n")))))
+      (make-directory (file-name-directory bib) t)
+      (with-temp-file bib (insert "% Global bibliography\n\n")))))
 
-;; org-cite: use CSL processor (no BibLaTeX/BibTeX toolchain needed)
+;; org-cite: CSL processor (no BibLaTeX toolchain needed)
 (after! oc
   (require 'citeproc)
   (setq org-cite-global-bibliography '("~/org/references.bib")
@@ -1838,7 +1841,7 @@ Skip for beamer exports — beamer uses adjustbox on plain tabular."
                                      (html csl)
                                      (t csl))))
 
-;; biblio.el: search and import references from online databases
+;; biblio.el: polite CrossRef access (required by their API policy)
 (after! biblio
   (setq biblio-crossref-user-email-address "martin@sukany.cz"))
 
@@ -1850,17 +1853,43 @@ Skip for beamer exports — beamer uses adjustbox on plain tabular."
       bibtex-autokey-titleword-length 5
       bibtex-autokey-titlewords 3)
 
+;; Helper: create new .bib file for a project
+(defun my/bib-new ()
+  "Create a new .bib file at prompted path."
+  (interactive)
+  (let ((path (read-file-name "New .bib file: " default-directory nil nil "refs.bib")))
+    (unless (file-exists-p path)
+      (make-directory (file-name-directory path) t)
+      (with-temp-file path
+        (insert (format "%% Bibliography: %s\n\n" (file-name-nondirectory path)))))
+    (find-file path)
+    (message "Created %s — add #+BIBLIOGRAPHY: %s to your org file" path path)))
+
+;; Helper: import from DOI (prompts for DOI, appends to current/global .bib)
+(defun my/bib-import-doi ()
+  "Fetch BibTeX for a DOI and append to the current .bib or global references.bib."
+  (interactive)
+  (require 'biblio-doi)
+  (let* ((doi (read-string "DOI (e.g. 10.1145/2898442.2898444): "))
+         (target (if (and buffer-file-name
+                         (string-suffix-p ".bib" buffer-file-name))
+                     buffer-file-name
+                   (car (ensure-list citar-bibliography)))))
+    (biblio-doi-insert-bibtex doi)
+    (message "Imported DOI %s" doi)))
+
 (map! :leader
       (:prefix ("B" . "bibliography")
        :desc "Browse references"        "b" #'citar-open
        :desc "Insert citation"          "i" #'citar-insert-citation
        :desc "Open notes for reference" "n" #'citar-open-notes
        :desc "Refresh bibliography"     "r" #'citar-refresh
+       :desc "New .bib file"            "N" #'my/bib-new
        :desc "Search CrossRef"          "s" #'biblio-crossref-lookup
        :desc "Search arXiv"             "a" #'biblio-arxiv-lookup
        :desc "Search DBLP"              "d" #'biblio-dblp-lookup
-       :desc "Import DOI → bib"         "D" #'biblio-doi-insert-bibtex
+       :desc "Import from DOI"          "D" #'my/bib-import-doi
-       :desc "Open .bib file"           "f" (cmd! (find-file (car citar-bibliography)))))
+       :desc "Open global .bib"         "f" (cmd! (find-file (expand-file-name "~/org/references.bib")))))
 
 
 ;;; ============================================================