profiler editor: filetype-driven fields and content view

- Show Size only for transparent/ber_tlv; Record length/count only for
  linear_fixed/cyclic; hide all size/record fields for df (unknown shows all)
- Hide the Contents section entirely for df (existence-only check)
- Changing file type clears now-inapplicable fields and resets content
  (keeps mode) when its kind switches between record and transparent
- profilerSetContent defaults content kind from the selected file type

Add profilerFileFields + profilerContentKindForFileType helpers + tests.
SW cache v45.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'otaman-v44';
+const CACHE = 'otaman-v45';
 const URLS = [
   'index.html',
   'help.html',