feat: Phase 2 - reliability & observability

- Circuit breaker: proper thresholds (3 failures, 30s timeout)
- HTTP timeouts: 30s on all providers (was no timeout)
- Structured logging: slog replaces fmt.Printf throughout
- Stream errors: propagated as SSE error events to client
- Registry fetch: retry with backoff (3 attempts)
- Registry reads in dashboard protected by RWMutex

internal/providers/circuit_breaker.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"time"
 
 	"github.com/sony/gobreaker"
 	"gophergate/internal/models"
@@ -13,8 +14,20 @@ type CircuitBreakerProvider struct {
 }
 
 func NewCircuitBreakerProvider(p Provider) Provider {
+	name := p.Name()
+	var maxRequests uint32 = 5
+	var interval = 60 * time.Second
+	var timeout = 30 * time.Second
+
 	settings := gobreaker.Settings{
-		Name: p.Name(),
+		Name:        name,
+		MaxRequests: maxRequests,
+		Interval:    interval,
+		Timeout:     timeout,
+		ReadyToTrip: func(counts gobreaker.Counts) bool {
+			// Trip after 3 consecutive failures
+			return counts.ConsecutiveFailures > 3
+		},
 	}
 	return &CircuitBreakerProvider{
 		provider: p,

internal/providers/deepseek.go

@@ -3,6 +3,7 @@ package providers
 import (
 	"bufio"
 	"context"
+	"time"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -21,7 +22,7 @@ type DeepSeekProvider struct {
 
 func NewDeepSeekProvider(cfg config.DeepSeekConfig, apiKey string) *DeepSeekProvider {
 	return &DeepSeekProvider{
-		client: resty.New(),
+		client: resty.New().SetTimeout(30 * time.Second),
 		config: cfg,
 		apiKey: apiKey,
 	}

internal/providers/gemini.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"time"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -19,7 +20,7 @@ type GeminiProvider struct {
 
 func NewGeminiProvider(cfg config.GeminiConfig, apiKey string) *GeminiProvider {
 	return &GeminiProvider{
-		client: resty.New(),
+		client: resty.New().SetTimeout(30 * time.Second),
 		config: cfg,
 		apiKey: apiKey,
 	}

internal/providers/grok.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"time"
 	"encoding/json"
 	"fmt"
 
@@ -18,7 +19,7 @@ type GrokProvider struct {
 
 func NewGrokProvider(cfg config.GrokConfig, apiKey string) *GrokProvider {
 	return &GrokProvider{
-		client: resty.New(),
+		client: resty.New().SetTimeout(30 * time.Second),
 		config: cfg,
 		apiKey: apiKey,
 	}

internal/providers/moonshot.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"time"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -19,7 +20,7 @@ type MoonshotProvider struct {
 
 func NewMoonshotProvider(cfg config.MoonshotConfig, apiKey string) *MoonshotProvider {
 	return &MoonshotProvider{
-		client: resty.New(),
+		client: resty.New().SetTimeout(30 * time.Second),
 		config: cfg,
 		apiKey: strings.TrimSpace(apiKey),
 	}

internal/providers/ollama.go

@@ -12,6 +12,7 @@ import (
 	"github.com/go-resty/resty/v2"
 	"gophergate/internal/config"
 	"gophergate/internal/models"
+	"log/slog"
 )
 
 type OllamaProvider struct {

internal/providers/openai.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"time"
 	"encoding/json"
 	"fmt"
 	"strings"