# Marketplace Diagnostics & Health Engine - Sprint 14

## Scope

Sprint 14 adds a development-only diagnostics feature for marketplace configuration and runtime health.

Constraints respected:
- No runtime behavior changes
- No business logic changes
- No authentication changes
- No payment changes

## Architecture

```text
src/app/features/diagnostics/
  components/
    diagnostics-page.component.*
  services/
    diagnostics-logger.service.ts
  models/
    diagnostics.model.ts
  validators/
    bootstrap-diagnostics.validator.ts
    runtime-diagnostics.validator.ts
    diagnostics-health-score.util.ts
  facade/
    diagnostics.facade.ts
```

## Health Checks

Current checks cover:
- bootstrap loaded
- tenant resolved
- runtime initialized
- theme loaded
- widget manifest loaded
- section engine reachable
- configuration engine initialized
- translations available
- required assets health

## Bootstrap Validation

Current validator detects:
- missing required properties
- unknown widget types
- duplicate page/section/widget ids
- unknown layout values
- invalid feature flags
- broken page definitions
- invalid navigation targets
- missing translations in navigation label keys
- missing branding media

## Runtime Validation

Current validator detects:
- missing datasource declarations for widgets that support them
- widget rendering failures from runtime diagnostics stream
- broken route expectations
- configuration fallback usage in local development
- failed image loading where DOM can observe it
- missing optional data

## Severity Model

Each entry includes:
- code
- severity
- title
- description
- affected component
- suggested resolution

Levels:
- info
- warning
- error
- critical

## Health Score

Simple weighted score:
- critical: -15
- error: -8
- warning: -3
- info: 0

Minimum 0, maximum 100.

## Developer Page

Development-only route:
- `/__diagnostics`

Page shows:
- summary
- health score
- passed checks
- warnings/errors/critical counts
- detailed diagnostics entries

## Logging Abstraction

`DiagnosticsLoggerService` stores diagnostic entries in memory.

`RuntimeDiagnosticsService` now keeps unknown widget events in memory for diagnostics consumption only.

No external logging integration in this sprint.

## Extension Points

Future additions can plug into:
- new validators under `validators/`
- new runtime event collectors
- remote diagnostics export service
- monitoring integrations (Sentry, Datadog, Grafana, OpenTelemetry)
- asset/network checks
- widget render timing checks

## Performance

Production route excluded.

Diagnostics work runs only on diagnostics page access in development mode.