feat: make streaming throttle interval and min growth configurable

Move hardcoded streamThrottleInterval (3s) and streamMinGrowth (200)
into StreamingConfig so they can be tuned per deployment via config
or environment variables.

pkg/channels/telegram/telegram.go

@@ -2,9 +2,9 @@ package telegram
 
 import (
 	"context"
-	"fmt"
 	"crypto/rand"
 	"encoding/binary"
+	"fmt"
 	"net/http"
 	"net/url"
 	"os"
@@ -798,10 +798,13 @@ func (c *TelegramChannel) BeginStream(ctx context.Context, chatID string) (chann
 		return nil, err
 	}
 
+	streamCfg := c.config.Channels.Telegram.Streaming
 	return &telegramStreamer{
 		bot:              c.bot,
 		chatID:           cid,
-		draftID: cryptoRandInt(), // non-zero random draft ID
+		draftID:          cryptoRandInt(),
+		throttleInterval: time.Duration(streamCfg.ThrottleSeconds) * time.Second,
+		minGrowth:        streamCfg.MinGrowthChars,
 	}, nil
 }
 
@@ -812,17 +815,14 @@ type telegramStreamer struct {
 	bot              *telego.Bot
 	chatID           int64
 	draftID          int
+	throttleInterval time.Duration
+	minGrowth        int
 	lastLen          int
 	lastAt           time.Time
 	failed           bool
 	mu               sync.Mutex
 }
 
-const (
-	streamThrottleInterval = 3 * time.Second
-	streamMinGrowth        = 200 // minimum character growth to send an update
-)
-
 func (s *telegramStreamer) Update(ctx context.Context, content string) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -834,7 +834,7 @@ func (s *telegramStreamer) Update(ctx context.Context, content string) error {
 	// Throttle: skip if not enough time or content has passed
 	now := time.Now()
 	growth := len(content) - s.lastLen
-	if s.lastLen > 0 && now.Sub(s.lastAt) < streamThrottleInterval && growth < streamMinGrowth {
+	if s.lastLen > 0 && now.Sub(s.lastAt) < s.throttleInterval && growth < s.minGrowth {
 		return nil
 	}
 

pkg/config/config.go

@@ -239,6 +239,8 @@ type PlaceholderConfig struct {
 
 type StreamingConfig struct {
 	Enabled         bool `json:"enabled,omitempty"          env:"PICOCLAW_CHANNELS_TELEGRAM_STREAMING_ENABLED"`
+	ThrottleSeconds int  `json:"throttle_seconds,omitempty" env:"PICOCLAW_CHANNELS_TELEGRAM_STREAMING_THROTTLE_SECONDS"`
+	MinGrowthChars  int  `json:"min_growth_chars,omitempty" env:"PICOCLAW_CHANNELS_TELEGRAM_STREAMING_MIN_GROWTH_CHARS"`
 }
 
 type WhatsAppConfig struct {

pkg/config/defaults.go

@@ -58,7 +58,7 @@ func DefaultConfig() *Config {
 					Enabled: true,
 					Text:    "Thinking... 💭",
 				},
-				Streaming: StreamingConfig{Enabled: true},
+				Streaming: StreamingConfig{Enabled: true, ThrottleSeconds: 3, MinGrowthChars: 200},
 			},
 			Feishu: FeishuConfig{
 				Enabled:           false,

pkg/providers/openai_compat/provider.go

@@ -248,7 +248,11 @@ func (p *Provider) ChatStream(
 }
 
 // parseStreamResponse parses an OpenAI-compatible SSE stream.
-func parseStreamResponse(ctx context.Context, reader io.Reader, onChunk func(accumulated string)) (*LLMResponse, error) {
+func parseStreamResponse(
+	ctx context.Context,
+	reader io.Reader,
+	onChunk func(accumulated string),
+) (*LLMResponse, error) {
 	var textContent strings.Builder
 	var finishReason string
 	var usage *UsageInfo