feat: add sidebar keybindings for journal navigation

Add keybindings to vulpea-ui-sidebar-mode-map for quick navigation:
- [ : Go to previous journal entry
- ] : Go to next journal entry
- t : Go to today's journal
- d : Pick a date

Commands use vulpea-journal-ui--visit-date to open notes in the main
window without disrupting the sidebar layout.

Author: d12frosted

CHANGELOG.org

@@ -2,6 +2,10 @@
 
 * Unreleased
 
+** Added
+
+- Sidebar keybindings for quick journal navigation: =[= (previous), =]= (next), =t= (today), =d= (pick date).
+
 * v1.0.0-rc.1
 
 Initial release candidate.

README.org

@@ -198,6 +198,17 @@ Reference orders for vulpea-ui widgets: stats=100, outline=200, backlinks=300, l
 | =vulpea-journal-previous= | Go to previous journal entry                            |
 | =vulpea-journal-setup=    | Enable calendar integration                             |
 
+* Sidebar Keybindings
+
+When viewing a journal note, the sidebar provides quick navigation:
+
+| Key | Action                         |
+|-----+--------------------------------|
+| =[= | Go to previous journal entry   |
+| =]= | Go to next journal entry       |
+| =t= | Go to today's journal          |
+| =d= | Pick a date                    |
+
 * Calendar Integration
 
 After calling =vulpea-journal-setup=, the Emacs calendar gains journal superpowers:

vulpea-journal-ui.el

@@ -159,11 +159,7 @@ This is the date of the journal entry you are currently viewing."
   "Visit journal for DATE from sidebar context.
 Opens the note in the main window, not the sidebar."
   (require 'vulpea-journal)
-  (let ((note (vulpea-journal-note date))
-        (main-win (vulpea-ui--get-main-window)))
-    (when main-win
-      (select-window main-win))
-    (vulpea-visit note)))
+  (vulpea-ui-visit-note (vulpea-journal-note date)))
 
 (defun vulpea-journal-ui--strip-drawers (text)
   "Remove org drawers from TEXT."
@@ -513,6 +509,60 @@ ON-SELECT is callback to handle date selection."
                       (format-time-string "%Y%m%d" (plist-get entry :date)))))))))
 
 
+;;; Sidebar Keybindings
+
+(declare-function vulpea-journal "vulpea-journal")
+(declare-function vulpea-journal-note-p "vulpea-journal")
+(declare-function vulpea-journal-note-date "vulpea-journal")
+(declare-function vulpea-journal--adjacent-date "vulpea-journal")
+(declare-function vulpea-journal--read-date "vulpea-journal")
+
+(defun vulpea-journal-ui--sidebar-note ()
+  "Get the current journal note from sidebar context.
+Works whether called from sidebar or main window."
+  (or vulpea-ui--current-note
+      (when-let ((main-win (vulpea-ui--get-main-window)))
+        (with-current-buffer (window-buffer main-win)
+          (when-let ((file (buffer-file-name)))
+            (car (vulpea-db-query-by-file-path file 0)))))))
+
+(defun vulpea-journal-ui-previous ()
+  "Navigate to the previous journal entry from sidebar."
+  (interactive)
+  (let ((note (vulpea-journal-ui--sidebar-note)))
+    (if (not (vulpea-journal-note-p note))
+        (user-error "Not viewing a journal note")
+      (if-let* ((current-date (vulpea-journal-note-date note))
+                (prev-date (vulpea-journal--adjacent-date current-date 'prev)))
+          (vulpea-journal-ui--visit-date prev-date)
+        (message "No previous journal entry")))))
+
+(defun vulpea-journal-ui-next ()
+  "Navigate to the next journal entry from sidebar."
+  (interactive)
+  (let ((note (vulpea-journal-ui--sidebar-note)))
+    (if (not (vulpea-journal-note-p note))
+        (user-error "Not viewing a journal note")
+      (if-let* ((current-date (vulpea-journal-note-date note))
+                (next-date (vulpea-journal--adjacent-date current-date 'next)))
+          (vulpea-journal-ui--visit-date next-date)
+        (message "No next journal entry")))))
+
+(defun vulpea-journal-ui-today ()
+  "Navigate to today's journal from sidebar."
+  (interactive)
+  (vulpea-journal-ui--visit-date (current-time)))
+
+(defun vulpea-journal-ui-date (date)
+  "Navigate to journal for DATE from sidebar."
+  (interactive (list (vulpea-journal--read-date)))
+  (vulpea-journal-ui--visit-date date))
+
+(define-key vulpea-ui-sidebar-mode-map (kbd "[") #'vulpea-journal-ui-previous)
+(define-key vulpea-ui-sidebar-mode-map (kbd "]") #'vulpea-journal-ui-next)
+(define-key vulpea-ui-sidebar-mode-map (kbd "t") #'vulpea-journal-ui-today)
+(define-key vulpea-ui-sidebar-mode-map (kbd "d") #'vulpea-journal-ui-date)
+
 ;;; Widget Registration
 
 (defun vulpea-journal-ui--get-order (widget)