Refactor annotation tool from WPF desktop app to .NET API

Replace the WPF desktop application (Azaion.Suite, Azaion.Annotator,
Azaion.Common, Azaion.Inference, Azaion.Loader, Azaion.LoaderUI,
Azaion.Dataset, Azaion.Test) with a standalone .NET Web API in src/.

Made-with: Cursor

.cursor/skills/plan/templates/component-spec.md

@@ -0,0 +1,156 @@
+# Component Specification Template
+
+Use this template for each component. Save as `components/[##]_[name]/description.md`.
+
+---
+
+```markdown
+# [Component Name]
+
+## 1. High-Level Overview
+
+**Purpose**: [One sentence: what this component does and its role in the system]
+
+**Architectural Pattern**: [e.g., Repository, Event-driven, Pipeline, Facade, etc.]
+
+**Upstream dependencies**: [Components that this component calls or consumes from]
+
+**Downstream consumers**: [Components that call or consume from this component]
+
+## 2. Internal Interfaces
+
+For each interface this component exposes internally:
+
+### Interface: [InterfaceName]
+
+| Method | Input | Output | Async | Error Types |
+|--------|-------|--------|-------|-------------|
+| `method_name` | `InputDTO` | `OutputDTO` | Yes/No | `ErrorType1`, `ErrorType2` |
+
+**Input DTOs**:
+```
+[DTO name]:
+  field_1: type (required/optional) — description
+  field_2: type (required/optional) — description
+```
+
+**Output DTOs**:
+```
+[DTO name]:
+  field_1: type — description
+  field_2: type — description
+```
+
+## 3. External API Specification
+
+> Include this section only if the component exposes an external HTTP/gRPC API.
+> Skip if the component is internal-only.
+
+| Endpoint | Method | Auth | Rate Limit | Description |
+|----------|--------|------|------------|-------------|
+| `/api/v1/...` | GET/POST/PUT/DELETE | Required/Public | X req/min | Brief description |
+
+**Request/Response schemas**: define per endpoint using OpenAPI-style notation.
+
+**Example request/response**:
+```json
+// Request
+{ }
+
+// Response
+{ }
+```
+
+## 4. Data Access Patterns
+
+### Queries
+
+| Query | Frequency | Hot Path | Index Needed |
+|-------|-----------|----------|--------------|
+| [describe query] | High/Medium/Low | Yes/No | Yes/No |
+
+### Caching Strategy
+
+| Data | Cache Type | TTL | Invalidation |
+|------|-----------|-----|-------------|
+| [data item] | In-memory / Redis / None | [duration] | [trigger] |
+
+### Storage Estimates
+
+| Table/Collection | Est. Row Count (1yr) | Row Size | Total Size | Growth Rate |
+|-----------------|---------------------|----------|------------|-------------|
+| [table_name] | | | | /month |
+
+### Data Management
+
+**Seed data**: [Required seed data and how to load it]
+
+**Rollback**: [Rollback procedure for this component's data changes]
+
+## 5. Implementation Details
+
+**Algorithmic Complexity**: [Big O for critical methods — only if non-trivial]
+
+**State Management**: [Local state / Global state / Stateless — explain how state is handled]
+
+**Key Dependencies**: [External libraries and their purpose]
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| [name] | [version] | [why needed] |
+
+**Error Handling Strategy**:
+- [How errors are caught, propagated, and reported]
+- [Retry policy if applicable]
+- [Circuit breaker if applicable]
+
+## 6. Extensions and Helpers
+
+> List any shared utilities this component needs that should live in a `helpers/` folder.
+
+| Helper | Purpose | Used By |
+|--------|---------|---------|
+| [helper_name] | [what it does] | [list of components] |
+
+## 7. Caveats & Edge Cases
+
+**Known limitations**:
+- [Limitation 1]
+
+**Potential race conditions**:
+- [Race condition scenario, if any]
+
+**Performance bottlenecks**:
+- [Bottleneck description and mitigation approach]
+
+## 8. Dependency Graph
+
+**Must be implemented after**: [list of component numbers/names]
+
+**Can be implemented in parallel with**: [list of component numbers/names]
+
+**Blocks**: [list of components that depend on this one]
+
+## 9. Logging Strategy
+
+| Log Level | When | Example |
+|-----------|------|---------|
+| ERROR | Unrecoverable failures | `Failed to process order {id}: {error}` |
+| WARN | Recoverable issues | `Retry attempt {n} for {operation}` |
+| INFO | Key business events | `Order {id} created by user {uid}` |
+| DEBUG | Development diagnostics | `Query returned {n} rows in {ms}ms` |
+
+**Log format**: [structured JSON / plaintext — match system standard]
+
+**Log storage**: [stdout / file / centralized logging service]
+```
+
+---
+
+## Guidance Notes
+
+- **Section 3 (External API)**: skip entirely for internal-only components. Include for any component that exposes HTTP endpoints, WebSocket connections, or gRPC services.
+- **Section 4 (Storage Estimates)**: critical for components that manage persistent data. Skip for stateless components.
+- **Section 5 (Algorithmic Complexity)**: only document if the algorithm is non-trivial (O(n^2) or worse, recursive, etc.). Simple CRUD operations don't need this.
+- **Section 6 (Helpers)**: if the helper is used by only one component, keep it inside that component. Only extract to `helpers/` if shared by 2+ components.
+- **Section 8 (Dependency Graph)**: this is essential for determining implementation order. Be precise about what "depends on" means — data dependency, API dependency, or shared infrastructure.