feat: Add APP_NAME env support for branding and deployment

- Make app name configurable via APP_NAME env variable - Update UI,
HTML, Docker, scripts, and k8s to use APP_NAME - Add process-html.sh for
template substitution - Document APP_NAME usage in
docs/APP_NAME_CONFIGURATION.md - Update Dockerfile, compose, and scripts
for dynamic naming - Add index.html.template for environment-based
branding

docs/APP_NAME_CONFIGURATION.md

@@ -0,0 +1,198 @@
+# APP_NAME Configuration Guide
+
+This document explains how the `APP_NAME` environment variable is used throughout the application to customize branding and naming.
+
+## Overview
+
+The `APP_NAME` environment variable allows you to customize the application name across all components, from the frontend UI to Docker containers and Kubernetes deployments.
+
+## Default Values
+
+- **Default APP_NAME**: `RxMinder`
+- **Package name fallback**: `rxminder` (lowercase)
+- **Docker tag fallback**: `meds` (for backward compatibility)
+
+## Usage Examples
+
+### Setting APP_NAME
+
+```bash
+# For deployment
+export APP_NAME="MyMedsApp"
+make deploy
+
+# For development
+export APP_NAME="DevMeds"
+npm run dev
+
+# For Docker build
+APP_NAME="CustomApp" docker build -t myapp .
+```
+
+### Environment Files
+
+```bash
+# .env
+APP_NAME=MyCustomApp
+
+# .env.production
+APP_NAME=ProductionApp
+
+# .env.staging
+APP_NAME=StagingApp
+```
+
+## Where APP_NAME is Used
+
+### 1. Frontend Application
+
+- **HTML Title**: `<title>$APP_NAME</title>`
+- **UI Header**: Button text shows `APP_NAME` value
+- **Environment Variable**: Available as `import.meta.env.VITE_APP_NAME`
+
+### 2. Docker Configuration
+
+- **Build Argument**: Passed to Dockerfile as `--build-arg APP_NAME=...`
+- **Container Names**: `${app_name_lower}-validation-test`
+- **Image Tags**: `${app_name_lower}-validation:latest`
+- **Docker Compose**: Labels include `app=${APP_NAME}`
+
+### 3. Kubernetes Deployment
+
+- **Resource Names**: `${APP_NAME}-frontend`, `${APP_NAME}-config`
+- **Labels**: `app: ${APP_NAME}`
+- **Container Image**: `${DOCKER_IMAGE:-registry/user/${APP_NAME}:latest}`
+
+### 4. Package Configuration
+
+- **Package Name**: `"name": "${APP_NAME:-rxminder}"`
+
+## File Locations
+
+### Files That Use APP_NAME
+
+1. **Frontend Files**:
+   - `index.html.template` - Page title
+   - `App.tsx` - UI header text
+   - `vite.config.ts` - Environment variable mapping
+
+2. **Docker Files**:
+   - `docker/Dockerfile` - Build argument and environment variable
+   - `docker/docker-compose.yaml` - Build args and labels
+
+3. **Kubernetes Templates**:
+   - `k8s/frontend-deployment.yaml.template` - Resource names and labels
+   - `k8s/configmap.yaml.template` - Resource names and labels
+   - All other `k8s/*.yaml.template` files
+
+4. **Scripts**:
+   - `scripts/deploy.sh` - Container and image naming
+   - `scripts/buildx-helper.sh` - Container and image naming
+   - `scripts/validate-deployment.sh` - Container and image naming
+   - `scripts/process-html.sh` - HTML template processing
+
+## Build Process
+
+### Development Mode
+
+1. `npm run predev` → Processes `index.html.template` → `index.html`
+2. `npm run dev` → Starts development server
+
+### Production Build
+
+1. Dockerfile processes `index.html.template` using `envsubst`
+2. Vite build uses processed `index.html`
+3. Final image contains customized HTML with correct title
+
+## Examples by Environment
+
+### Development Environment
+
+```bash
+# .env
+APP_NAME=MedsApp-Dev
+VITE_APP_NAME=MedsApp-Dev
+
+# Results in:
+# - HTML title: "MedsApp-Dev"
+# - UI header: "MedsApp-Dev"
+# - Docker containers: "medsapp-dev-validation-test"
+```
+
+### Staging Environment
+
+```bash
+# .env.staging
+APP_NAME=MedsApp-Staging
+
+# Results in:
+# - Kubernetes resources: "MedsApp-Staging-frontend"
+# - Docker images: "medsapp-staging-validation:latest"
+```
+
+### Production Environment
+
+```bash
+# .env.production
+APP_NAME=MedicationTracker
+
+# Results in:
+# - All resources branded as "MedicationTracker"
+# - Clean production naming
+```
+
+## Case Handling
+
+- **Frontend**: Uses original case (`MyApp`)
+- **Docker**: Converts to lowercase (`myapp`)
+- **Kubernetes**: Uses original case in labels, lowercase in DNS names
+
+## Troubleshooting
+
+### Common Issues
+
+1. **HTML title not updating**: Ensure `index.html.template` exists and `process-html.sh` runs
+2. **Docker build fails**: Check that `APP_NAME` doesn't contain invalid characters for Docker tags
+3. **Kubernetes deployment fails**: Verify `APP_NAME` follows Kubernetes naming conventions
+
+### Validation
+
+```bash
+# Test HTML processing
+APP_NAME=TestApp ./scripts/process-html.sh
+
+# Test Docker build
+APP_NAME=TestApp make deploy
+
+# Check generated files
+grep -r "TestApp" dist/
+```
+
+## Best Practices
+
+1. **Use consistent naming**: Keep `APP_NAME` consistent across all environments
+2. **Follow naming conventions**: Use alphanumeric characters and hyphens
+3. **Avoid special characters**: Docker and Kubernetes have naming restrictions
+4. **Document custom names**: Include `APP_NAME` in your deployment documentation
+
+## Migration from Hardcoded Values
+
+If you're migrating from hardcoded "meds" or "rxminder" references:
+
+1. Set `APP_NAME=meds` to maintain backward compatibility
+2. Test all deployment scripts with the new variable
+3. Gradually update to your preferred application name
+4. Update documentation and deployment guides
+
+## Environment Variable Precedence
+
+1. Command-line environment variable (`APP_NAME=...`)
+2. `.env` file in project root
+3. Default value (`RxMinder`)
+
+```bash
+# Priority order:
+APP_NAME=CmdLineApp make deploy    # Highest priority
+# vs .env file: APP_NAME=EnvFileApp
+# vs default: RxMinder             # Lowest priority
+```