Add queue hardening by modifying DeploymentJobTargets, DeploymentJobSteps, and DeploymentJobs tables

- Drop existing indexes on DeploymentJobTargets and DeploymentJobSteps
- Alter Status column to nvarchar(450) in DeploymentJobTargets, DeploymentJobSteps, and DeploymentJobs
- Add new columns: Finished, OutputMetadataJson, Started to DeploymentJobTargets; ErrorMessage, Finished, OutputMetadataJson, Started to DeploymentJobSteps; CorrelationId, HeartbeatAt, Priority, RowVersion, ScheduledAt, WorkerName to DeploymentJobs
- Create new indexes for improved query performance
- Add constraints to ensure OutputMetadataJson is valid JSON
- Record migration in __EFMigrationsHistory

.gitignore

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+# Build output
+bin/
+obj/
+out/
+publish/
+artifacts/
+
+# Visual Studio / Rider / VS Code
+.vs/
+.idea/
+.vscode/.ropeproject
+*.user
+*.suo
+*.rsuser
+*.sln.docstates
+*.csproj.user
+*.csproj.lscache
+
+# .NET / test artifacts
+TestResults/
+coverage/
+coverage.xml
+coverage.cobertura.xml
+*.trx
+*.coverage
+*.coveragexml
+
+# Logs / temp
+*.log
+*.tmp
+*.temp
+*.cache
+*.bak
+*.orig
+
+# Local configuration / secrets
+appsettings.Local.json
+appsettings.*.local.json
+appsettings.*.Local.json
+*.secrets.json
+secrets.json
+
+# EF / local tooling noise
+.ef/
+
+# OS files
+.DS_Store
+Thumbs.db
+desktop.ini
+
+# Node/Web artifacts if frontend files ever land here
+node_modules/
+dist/
+.env
+.env.local
+.env.*.local
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*