Redesign CSV templates with human-readable column headers

- Replace API field names (guestok, abe, ro, maproot_user, etc.) with
  plain-English headers (Guest Access, Access-Based Enumeration, Read Only,
  Map Root User, etc.) for customer clarity
- Drop comment rows that rendered poorly in spreadsheet apps
- Use two realistic example rows instead to teach by example
- Update csv_source.py to map friendly header names to API field names
  before validation and coercion (raw API names still accepted)
- Update README column reference to match new header names

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

smb_shares_template.csv

@@ -1,7 +1,3 @@
-name,path,comment,purpose,ro,browsable,guestok,abe,hostsallow,hostsdeny,timemachine,enabled
-# Required columns : name  path
-# purpose values   : NO_PRESET  DEFAULT_SHARE  ENHANCED_TIMEMACHINE  MULTI_PROTOCOL_NFS  PRIVATE_DATASETS  WORM_DROPBOX
-# List columns     : hostsallow  hostsdeny  (space-separated; e.g. "192.168.1.10 192.168.1.11")
-# Boolean columns  : ro  browsable  guestok  abe  timemachine  enabled  (true or false)
-# Lines starting with # are ignored.  Delete the example row below and add your shares.
-example-share,/mnt/pool/share,Example share description,NO_PRESET,false,true,false,false,,,false,true
+Share Name,Path,Description,Purpose,Read Only,Browsable,Guest Access,Access-Based Enumeration,Hosts Allow,Hosts Deny,Time Machine,Enabled
+Accounting,/mnt/tank/accounting,Accounting department files,NO_PRESET,false,true,false,false,,,false,true
+Public,/mnt/tank/public,Public read-only share,NO_PRESET,true,true,true,false,,,false,true