docs: add per package README for implementation details (AI generated with human review)

internal/api/v1/README.md

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+# API v1 Package
+
+Implements the v1 REST API handlers for GoDoxy, exposing endpoints for managing routes, Docker containers, certificates, metrics, and system configuration.
+
+## Overview
+
+The `internal/api/v1` package implements the HTTP handlers that power GoDoxy's REST API. It uses the Gin web framework and provides endpoints for route management, container operations, certificate handling, system metrics, and configuration.
+
+### Primary Consumers
+
+- **WebUI**: The homepage dashboard and admin interface consume these endpoints
+
+### Non-goals
+
+- Authentication and authorization logic (delegated to `internal/auth`)
+- Route proxying and request handling (handled by `internal/route`)
+- Docker container lifecycle management (delegated to `internal/docker`)
+- Certificate issuance and storage (handled by `internal/autocert`)
+
+### Stability
+
+This package is stable. Public API endpoints follow semantic versioning for request/response contracts. Internal implementation may change between minor versions.
+
+## Public API
+
+### Exported Types
+
+Types are defined in `goutils/apitypes`:
+
+| Type                       | Purpose                          |
+| -------------------------- | -------------------------------- |
+| `apitypes.ErrorResponse`   | Standard error response format   |
+| `apitypes.SuccessResponse` | Standard success response format |
+
+### Handler Subpackages
+
+| Package    | Purpose                                        |
+| ---------- | ---------------------------------------------- |
+| `route`    | Route listing, details, and playground testing |
+| `docker`   | Docker container management and monitoring     |
+| `cert`     | Certificate information and renewal            |
+| `metrics`  | System metrics and uptime information          |
+| `homepage` | Homepage items and category management         |
+| `file`     | Configuration file read/write operations       |
+| `auth`     | Authentication and session management          |
+| `agent`    | Remote agent creation and management           |
+
+## Architecture
+
+### Handler Organization
+
+Package structure mirrors the API endpoint paths (e.g., `auth/login.go` handles `/auth/login`).
+
+### Request Flow
+
+```mermaid
+sequenceDiagram
+    participant Client
+    participant GinRouter
+    participant Handler
+    participant Service
+    participant Response
+
+    Client->>GinRouter: HTTP Request
+    GinRouter->>Handler: Route to handler
+    Handler->>Service: Call service layer
+    Service-->>Handler: Data or error
+    Handler->>Response: Format JSON response
+    Response-->>Client: JSON or redirect
+```
+
+## Configuration Surface
+
+API listening address is configured with `GODOXY_API_ADDR` environment variable.
+
+## Dependency and Integration Map
+
+### Internal Dependencies
+
+| Package                 | Purpose                     |
+| ----------------------- | --------------------------- |
+| `internal/route/routes` | Route storage and iteration |
+| `internal/docker`       | Docker client management    |
+| `internal/config`       | Configuration access        |
+| `internal/metrics`      | System metrics collection   |
+| `internal/homepage`     | Homepage item generation    |
+| `internal/agentpool`    | Remote agent management     |
+| `internal/auth`         | Authentication services     |
+
+### External Dependencies
+
+| Package                        | Purpose                     |
+| ------------------------------ | --------------------------- |
+| `github.com/gin-gonic/gin`     | HTTP routing and middleware |
+| `github.com/gorilla/websocket` | WebSocket support           |
+| `github.com/moby/moby/client`  | Docker API client           |
+
+## Observability
+
+### Logs
+
+Handlers log at `INFO` level for requests and `ERROR` level for failures. Logs include:
+
+- Request path and method
+- Response status code
+- Error details (when applicable)
+
+### Metrics
+
+No dedicated metrics exposed by handlers. Request metrics collected by middleware.
+
+## Security Considerations
+
+- All endpoints (except `/api/v1/version`) require authentication
+- Input validation using Gin binding tags
+- Path traversal prevention in file operations
+- WebSocket connections use same auth middleware as HTTP
+
+## Failure Modes and Recovery
+
+| Failure                             | Behavior                                   |
+| ----------------------------------- | ------------------------------------------ |
+| Docker host unreachable             | Returns partial results with errors logged |
+| Certificate provider not configured | Returns 404                                |
+| Invalid request body                | Returns 400 with error details             |
+| Authentication failure              | Returns 302 redirect to login              |
+| Agent not found                     | Returns 404                                |
+
+## Usage Examples
+
+### Listing All Routes via WebSocket
+
+```go
+import (
+    "github.com/gorilla/websocket"
+)
+
+func watchRoutes(provider string) error {
+    url := "ws://localhost:8888/api/v1/route/list"
+    if provider != "" {
+        url += "?provider=" + provider
+    }
+
+    conn, _, err := websocket.DefaultDialer.Dial(url, nil)
+    if err != nil {
+        return err
+    }
+    defer conn.Close()
+
+    for {
+        _, message, err := conn.ReadMessage()
+        if err != nil {
+            return err
+        }
+        // message contains JSON array of routes
+        processRoutes(message)
+    }
+}
+```
+
+### Getting Container Status
+
+```go
+import (
+    "encoding/json"
+    "net/http"
+)
+
+type Container struct {
+    Server string `json:"server"`
+    Name   string `json:"name"`
+    ID     string `json:"id"`
+    Image  string `json:"image"`
+}
+
+func listContainers() ([]Container, error) {
+    resp, err := http.Get("http://localhost:8888/api/v1/docker/containers")
+    if err != nil {
+        return nil, err
+    }
+    defer resp.Body.Close()
+
+    var containers []Container
+    if err := json.NewDecoder(resp.Body).Decode(&containers); err != nil {
+        return nil, err
+    }
+    return containers, nil
+}
+```
+
+### Health Check
+
+```bash
+curl http://localhost:8888/health
+```
+
+)