BUG: Rhombus CLI flags (`-e`, `-f`) fail with syntax errors when using `racket -I rhombus`

When invoking Rhombus via the Racket CLI wrapper (racket -I rhombus), interaction flags like -e (eval) and -f (load file) fail with syntax errors. The CLI passes expressions directly to Racket's default #%top-interaction macro instead of routing them through Rhombus's parser.

Additionally, the interface mimics standard Racket too closely without actual support:

• The welcome banner incorrectly reads Welcome to Racket instead of Welcome to Rhombus.
• The --help output is identical to racket --help, listing numerous options (like -e, -f, -t) that are currently broken or unsupported under -I rhombus.

Steps to Reproduce

1. Evaluating any expression (-e) fails:

$ racket -I rhombus -e '"Hello, World"'
#%top-interaction: bad syntax
  in: #{(#%top-interaction . "Hello, World")}
  context...:
   /usr/racket/collects/syntax/parse/private/runtime-report.rkt:744:0: error/report
   /usr/racket/collects/syntax/parse/private/runtime-report.rkt:25:0: call-current-failure-handler

2. Running a script also fails (any file, even a simple file with only #lang rhombus and nothing else):

$ racket -I rhombus -f test.rhm
/home/sohang/a.rkt:1:6: #%top-interaction: expected one of these literal symbols: `multi' or `group'
  at: module
  in: #{#%top-interaction} module a #{(lib "rhombus/main.rhm")} #{(#%module-begin (multi (group "Hello, World!")))}
  location...:
   a.rkt:1:6
  context...:
   /usr/racket/collects/syntax/parse/private/runtime-report.rkt:744:0: error/report

Note: The only working CLI mechanism currently is launching the interactive REPL raw via racket -I rhombus with no trailing execution flags).

Start by reproducing the failures through the racket -I rhombus entry point with -e and -f, then trace how those flags reach #%top-interaction instead of the Rhombus parser. Check the banner and --help behavior as part of the same CLI surface. Done means supported flags execute Rhombus expressions and files correctly, while unsupported options and interface text are accurately represented.