feat: add bump-version.sh script for version management

Automates version bumps across all version source files:
- Cargo.toml (PRIMARY - workspace.package.version)
- debian/changelog (prepend new entry)
- debian/control (update Version field)
- scripts/build-package.sh (update VERSION variable)
- frontend/package.json (update version field)
- Stale references check after bump

Usage: ./scripts/bump-version.sh <new_version> <old_version>

migrations/017_enrollment_host_columns.sql

@@ -0,0 +1,5 @@
+-- Migration: 017_enrollment_host_columns
+-- Add missing columns for enrollment support
+ALTER TABLE hosts ADD COLUMN IF NOT EXISTS machine_id TEXT;
+ALTER TABLE certificates ADD COLUMN IF NOT EXISTS ip_address INET;
+ALTER TABLE certificates ADD COLUMN IF NOT EXISTS key_pem TEXT;