refactor(msg): single space between keyword and message, improve config suggestions

Tightens keyword formatting (ok/FAIL/hint/etc.) from two spaces to one.
Makes config key suggestions more generous: normalises spaces to
underscores, matches against leaf segments, and uses substring matching.
Updates all golden files.

testdata/mv.ct

@@ -1,8 +1,8 @@
 # Basic move
 $ pda set source@mvok value
 $ pda mv source@mvok dest@mvok
-  ok  renamed source@mvok to dest@mvok
+  ok renamed source@mvok to dest@mvok
 $ pda get dest@mvok
 value
 $ pda get source@mvok --> FAIL
-FAIL  cannot get 'source@mvok': no such key
+FAIL cannot get 'source@mvok': no such key