feat(bots): built-in bot runner + steamfree from UI

- BotRunner: server-side goroutine manager for built-in bot types
- steamfree bot embedded in server (polls Steam API, posts free games)
- bot_type + config JSONB columns on bots table
- Create/Update/Delete handlers manage runner lifecycle
- GET /bots/types returns registered bot types
- BotManager: type selector dropdown + config fields on create
- No SSH needed: create a 'Steam Free Games' bot from /bots/manage

internal/bot/steamfree.go

@@ -0,0 +1,116 @@
+package bot
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+// SteamFreeConfig is the config shape for bot_type "steamfree".
+type SteamFreeConfig struct {
+	ChannelID   string `json:"channel_id"`
+	PollMinutes int    `json:"poll_minutes"`
+}
+
+// SteamFreeBot polls Steam's featured categories for 100%-off games.
+func SteamFreeBot(ctx context.Context, raw json.RawMessage, send SendMessageFunc) {
+	var cfg SteamFreeConfig
+	if err := json.Unmarshal(raw, &cfg); err != nil || cfg.ChannelID == "" {
+		return
+	}
+	if cfg.PollMinutes <= 0 {
+		cfg.PollMinutes = 30
+	}
+
+	seen := map[int]bool{}
+	ticker := time.NewTicker(time.Duration(cfg.PollMinutes) * time.Minute)
+	defer ticker.Stop()
+
+	// Poll immediately on start
+	pollSteam(cfg.ChannelID, seen, send)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			pollSteam(cfg.ChannelID, seen, send)
+		}
+	}
+}
+
+func pollSteam(channelID string, seen map[int]bool, send SendMessageFunc) {
+	games, err := fetchFreeGames()
+	if err != nil {
+		return // ponytail: silent on error, logs add noise
+	}
+	for _, g := range games {
+		if seen[g.ID] {
+			continue
+		}
+		seen[g.ID] = true
+
+		msg := fmt.Sprintf(
+			"🎮 **FREE ON STEAM** 🎮\n**%s**\n~~$%.2f~~ → **FREE**\nhttps://store.steampowered.com/app/%d",
+			g.Name, float64(g.OriginalPrice)/100, g.ID,
+		)
+		send(channelID, msg)
+		time.Sleep(500 * time.Millisecond)
+	}
+}
+
+type featuredCategories struct {
+	Specials struct {
+		Items []struct {
+			ID            int    `json:"id"`
+			Name          string `json:"name"`
+			DiscountPct   int    `json:"discount_percent"`
+			FinalPrice    int    `json:"final_price"`
+			OriginalPrice int    `json:"original_price"`
+		} `json:"items"`
+	} `json:"specials"`
+}
+
+func fetchFreeGames() ([]struct {
+	ID            int    `json:"id"`
+	Name          string `json:"name"`
+	DiscountPct   int    `json:"discount_percent"`
+	FinalPrice    int    `json:"final_price"`
+	OriginalPrice int    `json:"original_price"`
+}, error) {
+	client := &http.Client{Timeout: 15 * time.Second}
+	resp, err := client.Get("https://store.steampowered.com/api/featuredcategories?cc=us&l=english")
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("steam: %d", resp.StatusCode)
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	var cats featuredCategories
+	if err := json.Unmarshal(body, &cats); err != nil {
+		return nil, err
+	}
+	var free []struct {
+		ID            int    `json:"id"`
+		Name          string `json:"name"`
+		DiscountPct   int    `json:"discount_percent"`
+		FinalPrice    int    `json:"final_price"`
+		OriginalPrice int    `json:"original_price"`
+	}
+	for _, item := range cats.Specials.Items {
+		if item.DiscountPct == 100 && item.OriginalPrice > 0 {
+			free = append(free, item)
+		}
+	}
+	return free, nil
+}
+
+