emrg: fix .iss LoadStringFromFile 2-param signature (v0.2.30 Build Release windows gate)

[argszero]

Summary

Fixes the v0.2.30 Build Release failure 31661378619 (windows-2025 'Make installer' step): iscc rejected the generated emrg.iss with Error on line 183 ... Invalid number of parameters.

Root cause

Inno Setup's Pascal Script API declares

function LoadStringFromFile(const FileName: String; var S: AnsiString): Boolean;

— a 2-parameter out-argument form, identical in iscc 6.7.1 through 7.x (verified against issrc Shared.ScriptFunc.pas at tags is-6_7_1 / is-6_7_3 / is-7_1_0 / main). #727's R125 log-surfacing code (merged in eb38234) called the non-existent 1-parameter string-returning form LogText := LoadStringFromFile(LogFile). The Test workflow never compiles the .iss, so the error only surfaced at tag-push Build Release — the v0.2.7 lesson recurring.

Changes

1. packaging/make-installer.sh — call LoadStringFromFile(LogFile, LogText) (out-param), keep the FileExists guard and 2000-char truncation; comment documents the real signature
2. tests/test_installer_stop.py — positive assert for the 2-param form + negative assert forbidding the 1-param form
3. .github/workflows/test.yml — new Inno Setup script compile smoke test step in the windows-2025 job: renders the emrg.iss heredoc (stub payload) and runs the runner's preinstalled iscc, so .iss syntax/signature errors fail PR CI instead of at release time

Verification

• Local pytest: 761 passed (incl. installer-stop suite 8/8)
• Rendered .iss compiles region verified; heredoc has no other unset $var expansions
• import run_client + emrg --help green

[argszero]

Closing as duplicate — consolidating into #731 (same iscc gate intent). Pushing the LoadStringFromFile 2-param signature fix (make-installer.sh) + regression test (test_installer_stop.py) onto #731's branch so the gate goes green and the v0.2.30 Build Release failure is actually fixed.