fix: add APP_VERSION fallback and HOST bind address env var (#952 #953) (#955)

* fix: add APP_VERSION fallback and HOST bind env var (#952 #953)

- Read package.json version when APP_VERSION env var is absent so the
  startup banner shows the correct version for source/Proxmox installs
- Add HOST env var to control the HTTP bind address; only applied when
  set so Docker deployments are unaffected (bind-all-interfaces default)
- Parse PORT as Number() so malformed values like '10.0.0.72:3001' fall
  back to 3001 instead of silently misbehaving
- Document HOST in .env.example, Environment-Variables wiki, and
  Install-Proxmox wiki with explicit warnings against using it in Docker

* fix: correct package.json path in APP_VERSION fallback

index.ts sits at server/src/ — one level up reaches server/package.json,
not two (../../ overshot to the repo root where no package.json exists).

server/.env.example

@@ -1,4 +1,5 @@
 PORT=3001 # Port to run the server on
+# HOST=0.0.0.0 # Bind address for the HTTP server. Only set this when running TREK from sources or via the Proxmox community script — never in Docker (the container handles binding).
 NODE_ENV=development # development = development mode; production = production mode
 # ENCRYPTION_KEY=<random-256-bit-hex>  # Separate key for encrypting stored secrets (API keys, MFA, SMTP, OIDC, etc.)
 # Auto-generated and persisted to ./data/.encryption_key if not set.