chore: add comprehensive .env.example and project resume

- Add complete .env.example template with all 15+ configuration sections
- Include Gitea SSH key configuration
- Update .gitignore to track .env.example while securing .env
- Add PROJECT_RESUME.md for development state tracking
- Create project directory structure

Resolves merge conflict with remote version by combining both
approaches: comprehensive documentation + SSH configuration.

.env.example

@@ -2,6 +2,12 @@
 # Copy this file to .env and fill in your values
 # NEVER commit .env to git - it contains sensitive data
 
+# =============================================================================
+# SSH KEY FOR GITEA
+# =============================================================================
+# Path to your SSH private key for Gitea authentication
+# GITEA_SSH_KEY_PATH=~/.ssh/id_ed25519_nexus
+
 # =============================================================================
 # APPLICATION MODE
 # =============================================================================