feat: add standalone agenda views for inbox, next, and wait states

Adds three new org-agenda-custom-commands:
- "i" for Inbox tasks (INBOX state)
- "n" for Next tasks (NEXT state)
- "w" for Waiting tasks (WAIT state)

These were previously only available as part of the composite "M" view.
Now they're exposed as standalone views for the org-agenda-api.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dotfiles/emacs.d/org-config.org

@@ -529,7 +529,11 @@ that have a SCHEDULED date before today to the current date."
                      ((org-agenda-overriding-header "Completion History:")
                       (org-agenda-ndays 5)
                       (org-agenda-entry-types '(:none))
-                      (org-agenda-start-with-log-mode '(state))))))))
+                      (org-agenda-start-with-log-mode '(state)))))
+          ,(cons "i" (cons "Inbox" inbox))
+          ,(cons "n" (cons "Next" next))
+          ("w" "Wait" todo "WAIT"
+           ((org-agenda-overriding-header "Waiting:"))))))
 #+end_src
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