chore: remove Replit/homegit references for public GitHub repo

- Simplify dev script (drop Replit-specific env vars)
- Remove REPLIT_* fallbacks from scripts/build.js
- Rewrite root README for GitHub (local build, no EAS, no homegit URLs)
- Update clone URL in artifacts README → GitHub
- Remove replit.md (Replit workspace descriptor, no longer needed)
- Untrack scripts/push-to-gitea.sh (internal-only, added to .gitignore)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

artifacts/postiz-mobile/scripts/build.js

@@ -55,20 +55,12 @@ function stripProtocol(domain) {
 }
 
 function getDeploymentDomain() {
-  if (process.env.REPLIT_INTERNAL_APP_DOMAIN) {
-    return stripProtocol(process.env.REPLIT_INTERNAL_APP_DOMAIN);
-  }
-
-  if (process.env.REPLIT_DEV_DOMAIN) {
-    return stripProtocol(process.env.REPLIT_DEV_DOMAIN);
-  }
-
   if (process.env.EXPO_PUBLIC_DOMAIN) {
     return stripProtocol(process.env.EXPO_PUBLIC_DOMAIN);
   }
 
   console.error(
-    "ERROR: No deployment domain found. Set REPLIT_INTERNAL_APP_DOMAIN, REPLIT_DEV_DOMAIN, or EXPO_PUBLIC_DOMAIN",
+    "ERROR: No deployment domain found. Set EXPO_PUBLIC_DOMAIN.",
   );
   process.exit(1);
 }
@@ -124,7 +116,7 @@ async function checkMetroHealth() {
 }
 
 function getExpoPublicReplId() {
-  return process.env.REPL_ID || process.env.EXPO_PUBLIC_REPL_ID;
+  return process.env.EXPO_PUBLIC_REPL_ID;
 }
 
 async function startMetro(expoPublicDomain, expoPublicReplId) {