Integrate BACKBEAT SDK and resolve KACHING license validation

Major integrations and fixes:
- Added BACKBEAT SDK integration for P2P operation timing
- Implemented beat-aware status tracking for distributed operations
- Added Docker secrets support for secure license management
- Resolved KACHING license validation via HTTPS/TLS
- Updated docker-compose configuration for clean stack deployment
- Disabled rollback policies to prevent deployment failures
- Added license credential storage (CHORUS-DEV-MULTI-001)

Technical improvements:
- BACKBEAT P2P operation tracking with phase management
- Enhanced configuration system with file-based secrets
- Improved error handling for license validation
- Clean separation of KACHING and CHORUS deployment stacks

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker/Dockerfile

@@ -1,7 +1,7 @@
 # CHORUS - Container-First P2P Task Coordination System
 # Multi-stage build for minimal production image
 
-FROM golang:1.21-alpine AS builder
+FROM golang:1.23-alpine AS builder
 
 # Install build dependencies
 RUN apk --no-cache add git ca-certificates
@@ -10,13 +10,16 @@ WORKDIR /build
 
 # Copy go mod files first (for better caching)
 COPY go.mod go.sum ./
-RUN go mod download
+
+# Copy vendor directory for local dependencies
+COPY vendor/ vendor/
 
 # Copy source code
 COPY . .
 
-# Build the CHORUS binary
+# Build the CHORUS binary with vendor mode
 RUN CGO_ENABLED=0 GOOS=linux go build \
+    -mod=vendor \
     -ldflags='-w -s -extldflags "-static"' \
     -o chorus \
     ./cmd/chorus