feat: adds --readonly and --pin flags, and displays Size column in list by default

testdata/meta.ct

@@ -3,6 +3,8 @@ $ pda set hello@m world
 $ pda meta hello@m
   key: hello@m
   secret: false
+  writable: true
+  pinned: false
   expires: never
 
 # View metadata for an encrypted key
@@ -10,4 +12,6 @@ $ pda set --encrypt secret@m hunter2
 $ pda meta secret@m
   key: secret@m
   secret: true
+  writable: true
+  pinned: false
   expires: never