v0.3.4

Patch release. Fixes four classes of failure surfaced by running
every command against a real MainWP Dashboard.

1. Default gum output was unimplemented (lib/output.sh)
   mainwp_render_table had branches for json and plain, but
   the default 'table' branch (with gum installed) fell straight
   through to return 0 without printing anything. Wire up
   gum table --separator ';' for the styled case, and wrap the
   gum call in a try-or-fallback so any gum failure silently
   degrades to plain text.

2. gum broke on TTY-less shells (lib/output.sh)
   gum table tries to open /dev/tty for its alternate-screen
   buffer and exits non-zero, swallowing the output. The fix:
   only attempt the gum path when [[ -t 1 ]]. The same gate
   applies to mainwp_render_object, which used column -t and
   died with 'line too long' on any payload containing a long
   value (URL, embedded JSON). Replace with a printf-width
   formatter that has no line-length limit.

3. List endpoints with array values printed multi-line junk
   (lib/output.sh). The plain and gum paths now use
   .permissions | join(", ") so
   permissions: ["Read", "Write & Delete"] becomes a single
   comma-separated cell that fits one row.

4. The API has at least four response shapes; the extractor
   only handled one (lib/commands/_common.sh). The new
   _mainwp_extract_list handles:

   • a bare array [a, b]
   • {data: [a, b]} unwrap
   • {data: {k: [users]}} (e.g. /users) recurse
   • {k: obj, k: obj, ...} (e.g. /tags) flatten
     An earlier revision also embedded the jq program inside
     $'...\n\t...', which under certain quoting combinations left
     the \n and \t markers literal and made jq silently return
     empty. Use one-line jq programs on stdin to avoid the trap.

In addition:

• lib/api.sh: mainwp_api_get and mainwp_api_delete no
  longer have an implicit body argument. Their signatures
  are mainwp_api_get path extras... where every extra
  positional is treated as a query-string pair. Same root
  cause as the earlier init per_page=1 bug: the third
  positional was the body, not a query arg, and GET endpoints
  were silently treating the query filter as the request body
  and returning 400.
• lib/commands/users.sh: cmd_users_list was bypassing
  the extractor entirely. Now it goes through
  _mainwp_extract_list, so users show up as a real table
  with a site column.
• lib/commands/sites.sh: _mainwp_extract_sites is now
  a thin shim around _mainwp_extract_list.

Verified end-to-end against the real dashboard (26/27 read
endpoints passing; the one remaining failure, posts list --websites 45, is a server-side HTTP 500 and is not a CLI
issue). 61 smoke tests, all passing.