Adauga write-back text->binar VFP: txt2vcx.ps1 + vfp_filemap.ps1 + test_roundtrip.ps1

Fluxul complet bin->text->edit->bin pentru .vcx/.scx (faza 1; .mnx/.frx raman
read-only): regenerare+compilare in staging unic per rulare, guard-uri
(COMUN cu -AllowComun, staleness, binar lipsa, folder foxbin2prg), fidelity
check pe octeti inainte de orice copiere, copiere .vct->.vcx cu restaurare
la esec partial, refresh cache. Harta de extensii extrasa in vfp_filemap.ps1,
dot-sourced si de vcx2txt.ps1 (comportament identic).

Invoke-FoxBin2PrgSafe: wrapper cu timeout+taskkill pentru toate invocarile
exe-ului - la text stricat Prg2Bin intoarce ErrorLevel 0 dar binarul corupt
poate ridica MessageBox modal VFP nesuprimabil la reconversie.

test_roundtrip.ps1: faze fidelitate/editare/smoke siblings/negativ+guard-uri,
41 PASS pe ROAGEST + smoke ROAIMOB/ROAACNPRO.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

vcx2txt.ps1

@@ -66,11 +66,9 @@ if (-not (Test-Path $exe)) {
     throw "Nu gasesc $exe. Compileaza intai FoxBin2Prg (deschide foxbin2prg.pj2 in VFP si Build)."
 }
 
-# binar -> (memo, extensie text)
-$map = @{
-    '.vcx' = @('.vct', '.vc2'); '.scx' = @('.sct', '.sc2'); '.frx' = @('.frt', '.fr2')
-    '.lbx' = @('.lbt', '.lb2'); '.mnx' = @('.mnt', '.mn2'); '.dbc' = @('.dct', '.dc2')
-}
+# binar -> (memo, extensie text) -- harta comuna, partajata cu txt2vcx.ps1
+. (Join-Path $PSScriptRoot 'vfp_filemap.ps1')
+$map = $script:VfpFileMap
 
 function Convert-One($fullPath) {
     $f = Get-Item -LiteralPath $fullPath