feat: add nightly branch workflow

docs/implementation/PHASE5_FINAL_STATUS.md

@@ -28,6 +28,7 @@ Phase 5 Custom DNS Provider Plugins Backend has been **successfully implemented*
 ## Implementation Highlights
 
 ### 1. Plugin Architecture ✅
+
 - Thread-safe global registry with RWMutex
 - Interface versioning (v1) for compatibility
 - Lifecycle hooks (Init/Cleanup)
@@ -35,6 +36,7 @@ Phase 5 Custom DNS Provider Plugins Backend has been **successfully implemented*
 - Dual Caddy config builders
 
 ### 2. Built-in Providers (10) ✅
+
 ```
 1. Cloudflare        6. Namecheap
 2. AWS Route53       7. GoDaddy
@@ -44,6 +46,7 @@ Phase 5 Custom DNS Provider Plugins Backend has been **successfully implemented*
 ```
 
 ### 3. Security Features ✅
+
 - SHA-256 signature verification
 - Directory permission validation
 - Platform restrictions (Linux/macOS only)
@@ -51,6 +54,7 @@ Phase 5 Custom DNS Provider Plugins Backend has been **successfully implemented*
 - Admin-only API access
 
 ### 4. Example Plugin ✅
+
 - PowerDNS implementation complete
 - Compiles to 14MB shared object
 - Full ProviderPlugin interface
@@ -58,6 +62,7 @@ Phase 5 Custom DNS Provider Plugins Backend has been **successfully implemented*
 - Build instructions documented
 
 ### 5. Test Coverage ✅
+
 ```
 Overall Coverage: 85.1%
 Test Files:
@@ -73,6 +78,7 @@ Test Results: ALL PASS
 ## File Inventory
 
 ### Created Files (18)
+
 ```
 backend/pkg/dnsprovider/builtin/
   cloudflare.go, route53.go, digitalocean.go
@@ -100,6 +106,7 @@ docs/implementation/
 ```
 
 ### Modified Files (5)
+
 ```
 backend/internal/services/dns_provider_service.go
 backend/internal/caddy/config.go
@@ -115,12 +122,14 @@ backend/internal/api/handlers/dns_provider_handler_test.go
 ## Build Verification
 
 ### Backend Build
+
 ```bash
 $ cd backend && go build -v ./...
 ✅ SUCCESS - All packages compile
 ```
 
 ### PowerDNS Plugin Build
+
 ```bash
 $ cd plugins/powerdns
 $ CGO_ENABLED=1 go build -buildmode=plugin -o powerdns.so main.go
@@ -128,6 +137,7 @@ $ CGO_ENABLED=1 go build -buildmode=plugin -o powerdns.so main.go
 ```
 
 ### Test Execution
+
 ```bash
 $ cd backend && go test -v -coverprofile=coverage.txt ./...
 ✅ SUCCESS - 85.1% coverage (target: ≥85%)
@@ -165,18 +175,21 @@ POST   /api/admin/plugins/reload   - Reload all plugins
 ## Known Limitations
 
 ### Platform Constraints
+
 - **Linux/macOS Only**: Go plugin system limitation
 - **CGO Required**: Must build with `CGO_ENABLED=1`
 - **Version Matching**: Plugin and Charon must use same Go version
 - **Same Architecture**: x86-64, ARM64, etc. must match
 
 ### Operational Constraints
+
 - **No Hot Reload**: Requires application restart to reload plugins
 - **Large Binaries**: Each plugin ~14MB (Go runtime embedded)
 - **Same Process**: Plugins run in same memory space as Charon
 - **Load Time**: ~100ms startup overhead per plugin
 
 ### Security Considerations
+
 - **SHA-256 Only**: File integrity check, not cryptographic signing
 - **No Sandboxing**: Plugins have full process access
 - **Directory Permissions**: Relies on OS-level security
@@ -186,11 +199,13 @@ POST   /api/admin/plugins/reload   - Reload all plugins
 ## Documentation
 
 ### User Documentation
+
 - [PHASE5_PLUGINS_COMPLETE.md](./PHASE5_PLUGINS_COMPLETE.md) - Comprehensive implementation guide
 - [PHASE5_SUMMARY.md](./PHASE5_SUMMARY.md) - Quick reference summary
 - [PHASE5_CHECKLIST.md](./PHASE5_CHECKLIST.md) - Implementation checklist
 
 ### Developer Documentation
+
 - [plugins/powerdns/README.md](../../plugins/powerdns/README.md) - Plugin development guide
 - Inline code documentation in all files
 - API endpoint documentation
@@ -233,6 +248,7 @@ From specification: *"Return when: All backend code implemented, Tests passing w
 ## Next Steps
 
 ### Phase 6: Frontend Implementation
+
 - Plugin management UI
 - Provider selection interface
 - Credential configuration forms
@@ -240,6 +256,7 @@ From specification: *"Return when: All backend code implemented, Tests passing w
 - Real-time loading indicators
 
 ### Future Enhancements (Not Required)
+
 - Cryptographic signing (GPG/RSA)
 - Hot reload capability
 - Plugin marketplace integration
@@ -267,11 +284,13 @@ From specification: *"Return when: All backend code implemented, Tests passing w
 ## Quick Reference
 
 ### Environment Variables
+
 ```bash
 CHARON_PLUGINS_DIR=/opt/charon/plugins
 ```
 
 ### Build Commands
+
 ```bash
 # Backend
 cd backend && go build -v ./...
@@ -282,6 +301,7 @@ CGO_ENABLED=1 go build -buildmode=plugin -o yourplugin.so main.go
 ```
 
 ### Test Commands
+
 ```bash
 # Full test suite with coverage
 cd backend && go test -v -coverprofile=coverage.txt ./...
@@ -291,6 +311,7 @@ go test -v ./pkg/dnsprovider/builtin/...
 ```
 
 ### Plugin Deployment
+
 ```bash
 mkdir -p /opt/charon/plugins
 cp yourplugin.so /opt/charon/plugins/