feat: add migrate command, media server detection, and debrid auto-config

- Migration wizard from Sonarr/Radarr/Prowlarr (unarr migrate) [pre-beta]
  - Auto-detect instances via Docker, config files, port scan, Prowlarr
  - Import wanted list (monitored+missing movies/series)
  - Import download history and blocklist to avoid re-downloading
  - Extract debrid tokens from *arr download clients
  - Quality profile mapping to preferred_quality config
  - DISTINCT ON PostgreSQL query for optimal torrent selection
  - JSON export with --dry-run --json (text to stderr, JSON to stdout)
- Media server detection (Plex/Jellyfin/Emby) in unarr init
  - Detects library paths and offers them as download directory options
- Debrid auto-configuration in unarr init
  - Scans *arr instances for debrid tokens
  - Validates and saves via API if user confirms
- New preferred_quality setting in config (2160p/1080p/720p)
- Library scan command (unarr scan) with ffprobe metadata extraction

internal/arr/client.go

@@ -0,0 +1,188 @@
+package arr
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Client talks to a single *arr instance (Sonarr, Radarr, or Prowlarr).
+type Client struct {
+	baseURL string
+	apiKey  string
+	httpClient *http.Client
+}
+
+// NewClient creates a client for the given *arr instance.
+func NewClient(baseURL, apiKey string) *Client {
+	return &Client{
+		baseURL: strings.TrimRight(baseURL, "/"),
+		apiKey:  apiKey,
+		httpClient: &http.Client{Timeout: 15 * time.Second},
+	}
+}
+
+// SystemStatus returns version and app info. Works with all *arr apps.
+func (c *Client) SystemStatus() (*SystemStatus, error) {
+	// Try v3 first (Sonarr/Radarr), then v1 (Prowlarr)
+	var s SystemStatus
+	if err := c.get("/api/v3/system/status", &s); err != nil {
+		if err2 := c.get("/api/v1/system/status", &s); err2 != nil {
+			return nil, fmt.Errorf("system/status v3: %w; v1: %v", err, err2)
+		}
+	}
+	return &s, nil
+}
+
+// ── Radarr ──────────────────────────────────────────────────────────
+
+func (c *Client) Movies() ([]Movie, error) {
+	var m []Movie
+	if err := c.get("/api/v3/movie", &m); err != nil {
+		return nil, fmt.Errorf("movies: %w", err)
+	}
+	return m, nil
+}
+
+// ── Sonarr ──────────────────────────────────────────────────────────
+
+func (c *Client) Series() ([]Series, error) {
+	var s []Series
+	if err := c.get("/api/v3/series", &s); err != nil {
+		return nil, fmt.Errorf("series: %w", err)
+	}
+	return s, nil
+}
+
+// ── Shared (Sonarr + Radarr use the same v3 endpoints) ─────────────
+
+func (c *Client) QualityProfiles() ([]QualityProfile, error) {
+	var p []QualityProfile
+	if err := c.get("/api/v3/qualityprofile", &p); err != nil {
+		return nil, fmt.Errorf("quality profiles: %w", err)
+	}
+	return p, nil
+}
+
+func (c *Client) RootFolders() ([]RootFolder, error) {
+	var f []RootFolder
+	if err := c.get("/api/v3/rootfolder", &f); err != nil {
+		return nil, fmt.Errorf("root folders: %w", err)
+	}
+	return f, nil
+}
+
+func (c *Client) DownloadClients() ([]DownloadClient, error) {
+	var d []DownloadClient
+	if err := c.get("/api/v3/downloadclient", &d); err != nil {
+		return nil, fmt.Errorf("download clients: %w", err)
+	}
+	return d, nil
+}
+
+// DownloadClientDetails returns the full config (including fields) for a single download client.
+func (c *Client) DownloadClientDetails(id int) ([]Field, error) {
+	path := fmt.Sprintf("/api/v3/downloadclient/%d", id)
+	var dc struct {
+		Fields []Field `json:"fields"`
+	}
+	if err := c.get(path, &dc); err != nil {
+		return nil, err
+	}
+	return dc.Fields, nil
+}
+
+// ── Shared (Sonarr + Radarr) ────────────────────────────────────────
+
+func (c *Client) Tags() ([]Tag, error) {
+	var t []Tag
+	if err := c.get("/api/v3/tag", &t); err != nil {
+		return nil, fmt.Errorf("tags: %w", err)
+	}
+	return t, nil
+}
+
+// History returns download history records (grabbed + imported).
+// pageSize controls how many records per page (max 250).
+func (c *Client) History(pageSize int) ([]HistoryRecord, error) {
+	if pageSize <= 0 {
+		pageSize = 250
+	}
+	path := fmt.Sprintf("/api/v3/history?page=1&pageSize=%d&sortKey=date&sortDirection=descending", pageSize)
+	var resp HistoryResponse
+	if err := c.get(path, &resp); err != nil {
+		return nil, fmt.Errorf("history: %w", err)
+	}
+	return resp.Records, nil
+}
+
+// Blocklist returns releases the user has explicitly rejected.
+func (c *Client) Blocklist(pageSize int) ([]BlocklistItem, error) {
+	if pageSize <= 0 {
+		pageSize = 250
+	}
+	path := fmt.Sprintf("/api/v3/blocklist?page=1&pageSize=%d", pageSize)
+	var resp BlocklistResponse
+	if err := c.get(path, &resp); err != nil {
+		return nil, fmt.Errorf("blocklist: %w", err)
+	}
+	return resp.Records, nil
+}
+
+// ── Prowlarr ────────────────────────────────────────────────────────
+
+func (c *Client) Indexers() ([]Indexer, error) {
+	var idx []Indexer
+	if err := c.get("/api/v1/indexer", &idx); err != nil {
+		return nil, fmt.Errorf("indexers: %w", err)
+	}
+	return idx, nil
+}
+
+func (c *Client) Applications() ([]Application, error) {
+	var apps []Application
+	if err := c.get("/api/v1/applications", &apps); err != nil {
+		return nil, fmt.Errorf("applications: %w", err)
+	}
+	return apps, nil
+}
+
+// ── HTTP helper ─────────────────────────────────────────────────────
+
+func (c *Client) get(path string, dst any) error {
+	req, err := http.NewRequest(http.MethodGet, c.baseURL+path, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("X-Api-Key", c.apiKey)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 50<<20)) // 50MB limit for large libraries
+	if err != nil {
+		return fmt.Errorf("read body: %w", err)
+	}
+
+	if resp.StatusCode == http.StatusUnauthorized {
+		return fmt.Errorf("unauthorized — check your API key")
+	}
+	if resp.StatusCode >= 400 {
+		msg := string(body)
+		if len(msg) > 200 {
+			msg = msg[:200] + "..."
+		}
+		return fmt.Errorf("HTTP %d: %s", resp.StatusCode, msg)
+	}
+
+	if err := json.Unmarshal(body, dst); err != nil {
+		return fmt.Errorf("decode JSON: %w", err)
+	}
+	return nil
+}