feat(v3.0.0): unify platform architecture and introduce feature tiers

* consolidate DomainReport as canonical data model
* add feature tier system (free/pro/data+ scaffolding)
* apply clean feature gating across workflows and tracking
* refactor app structure for maintainability
* standardize navigation and settings
* add data lifecycle controls
* ensure consistency across UI, export, and CLI
* stabilize internal inspection API

1 files changed, 48 insertions, 0 deletions

diff --git a/Docs/ARCHITECTURE.md b/Docs/ARCHITECTURE.md
new file mode 100644
index 0000000..0d364d6
--- /dev/null
+++ b/Docs/ARCHITECTURE.md
@@ -0,0 +1,48 @@
+# DomainDig v3.0.0 Architecture
+
+## Overview
+
+DomainDig is a local-first inspection platform built around one canonical output model: `DomainReport`.
+
+Inspection flow:
+
+1. `DomainInspectionService.inspect(domain:)` gathers live and cached section data into `LookupSnapshot`.
+2. `DomainReportBuilder` converts the snapshot into a canonical `DomainReport`.
+3. UI, exports, and CLI rendering derive from `DomainReport`.
+
+`LookupSnapshot` remains an internal collection and persistence shape. `DomainReport` is the stable presentation and export contract.
+
+## Canonical Report Lifecycle
+
+- `LookupRuntime` coordinates section services.
+- `DomainInspectionService` normalizes failures, provenance, cache state, and section metadata.
+- `DomainReportBuilder` adds summaries, insights, risk scoring, change analysis, workflow context, and report metadata.
+- `DomainReportExporter` renders TXT, CSV, and JSON from the same report payload.
+- `DomainDigCLI` prints exporter output directly so CLI output matches the app.
+
+## Feature Tiers
+
+The app now uses `FeatureAccessService` as the single feature gating surface.
+
+- `Free`: single lookup, basic history, limited tracking
+- `Pro`: workflows, batch operations, advanced exports
+- `Data+`: future historical datasets and extended enrichment
+
+Current release behavior is static scaffolding only. There are no purchases, backend checks, or remote entitlements.
+
+## Data Boundaries
+
+- Inspection services: network collection only
+- `DomainReportBuilder`: canonical model assembly
+- `FeatureAccessService`: tier and capability checks
+- `DomainViewModel`: UI orchestration, persistence, batch coordination
+- Views: rendering and interaction only
+
+## Adding a New Data Source
+
+1. Add the raw collection call to `LookupRuntime`.
+2. Integrate it in `DomainInspectionService` with provenance, cache source, and normalized failures.
+3. Extend `LookupSnapshot` only if the raw result must persist.
+4. Add the summarized representation to `DomainReportBuilder`.
+5. Expose it through `DomainReportExporter` if it should appear in TXT, CSV, JSON, or CLI.
+6. Render the new summary in SwiftUI using `DomainReport` fields.