docs: align fasm2 command template - #3

Summary

• Document the checked-in default Fasm2CommandTemplate value in both the root README and beginner user guide.
• Align troubleshooting guidance with whp16.ini, which includes -e 5 in the default %SCRIPT% -e 5 %SOURCE% %OUTPUT% assembler bridge command.

Verification

• Ad-hoc verification: /tmp/hermes-verify-whp16-fasm2-docs-0gxub59_.py checked that whp16.ini defines %SCRIPT% -e 5 %SOURCE% %OUTPUT%, both Markdown docs contain that exact template, the stale %SCRIPT% %SOURCE% %OUTPUT% text is gone, fasm2.cmd still points at the submodule fasm2\\fasmg bridge, and git diff --check HEAD passes.
• Cleanup: the temporary verifier was removed after it exited 0.

Notes / Limitations

• Documentation-only change; no WHP runtime or Windows assembler build was run from this Linux cron environment.
• Existing open PR chore: ignore generated WHP16 module binaries #2 is a non-overlapping .gitignore hygiene change for generated module binaries.