Fix component name regex to support : and / in paths

The dep scanner regex only matched [a-zA-Z0-9_-] in component names,
missing the new path separators (/) and namespace delimiters (:).
Fixed in deps.sx spec + rebootstrapped sx_ref.py and sx-browser.js.
Also fixed the Python fallback in deps.py.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/ref/deps.sx

@@ -121,7 +121,7 @@
 
 (define scan-components-from-source :effects []
   (fn ((source :as string))
-    (let ((matches (regex-find-all "\\(~([a-zA-Z_][a-zA-Z0-9_\\-]*)" source)))
+    (let ((matches (regex-find-all "\\(~([a-zA-Z_][a-zA-Z0-9_\\-:/]*)" source)))
       (map (fn ((m :as string)) (str "~" m)) matches))))