Remove configurable APP_VERSION and define it in code

The APP_VERSION variable is no longer configurable via the `.env` file or environment settings. Instead, the version is now hardcoded in `backend/app/core/config.py` as `NEXAPG_VERSION` and accessed through a property. This change simplifies version control and ensures consistency across deployments.

.env.example

@@ -3,8 +3,6 @@
 # ------------------------------
 # Display name used in API docs/UI.
 APP_NAME=NexaPG Monitor
-# Manual version string shown in Service Information page.
-APP_VERSION=0.1.0
 # Runtime environment: dev | staging | prod | test
 ENVIRONMENT=dev
 # Backend log level: DEBUG | INFO | WARNING | ERROR

README.md

@@ -142,7 +142,6 @@ Note: Migrations run automatically when the backend container starts (`entrypoin
 | Variable | Description |
 |---|---|
 | `APP_NAME` | Application display name |
-| `APP_VERSION` | Displayed NexaPG version in Service Information |
 | `ENVIRONMENT` | Runtime environment (`dev`, `staging`, `prod`, `test`) |
 | `LOG_LEVEL` | Backend log level (`DEBUG`, `INFO`, `WARNING`, `ERROR`) |
 
@@ -238,6 +237,7 @@ Recommended values for `VITE_API_URL`:
 - Displays current version, latest known version, uptime, host, and platform
 - "Check for Updates" against the latest published release in the official upstream repository (`git.nesterovic.cc/nessi/NexaPG`)
 - Version/update source are read-only in UI (maintainer-controlled in code/release flow)
+- Local displayed version is code-defined in `backend/app/core/config.py` (`NEXAPG_VERSION`) and not configurable via `.env`
 
 ## Target Owner Notifications
 

backend/app/core/config.py

@@ -2,12 +2,13 @@ from functools import lru_cache
 from pydantic import field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
+NEXAPG_VERSION = "0.1.1"
+
 
 class Settings(BaseSettings):
     model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")
 
     app_name: str = "NexaPG Monitor"
-    app_version: str = "0.1.0"
     environment: str = "dev"
     api_v1_prefix: str = "/api/v1"
     log_level: str = "INFO"
@@ -33,6 +34,10 @@ class Settings(BaseSettings):
     init_admin_email: str = "admin@example.com"
     init_admin_password: str = "ChangeMe123!"
 
+    @property
+    def app_version(self) -> str:
+        return NEXAPG_VERSION
+
     @property
     def database_url(self) -> str:
         return (