Implement structured logging with slog

- Replace zerolog with Go's standard slog package
- Add ColorHandler for terminal color output
- Add context-aware logging system
- Format attributes on the same line as log messages
- Use green color for INFO level logs
- Set up context value extraction helpers

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

contextutil/context.go

@@ -0,0 +1,89 @@
+package contextutil
+
+import (
+	"context"
+	"time"
+
+	"git.antanst.com/antanst/uid"
+)
+
+// ContextKey type for context values
+type ContextKey string
+
+// Context keys
+const (
+	CtxKeyURL       ContextKey = "url"        // Full URL being processed
+	CtxKeyHost      ContextKey = "host"       // Host of the URL
+	CtxKeyRequestID ContextKey = "request_id" // Unique ID for this processing request
+	CtxKeyWorkerID  ContextKey = "worker_id"  // Worker ID processing this request
+	CtxKeyStartTime ContextKey = "start_time" // When processing started
+	CtxKeyComponent ContextKey = "component"  // Component name for logging
+)
+
+// NewRequestContext creates a new, cancellable context
+// with a timeout and
+func NewRequestContext(parentCtx context.Context, url string, host string, workerID int) (context.Context, context.CancelFunc) {
+	ctx, cancel := context.WithTimeout(parentCtx, 120*time.Second)
+	requestID := uid.UID()
+	ctx = context.WithValue(ctx, CtxKeyURL, url)
+	ctx = context.WithValue(ctx, CtxKeyHost, host)
+	ctx = context.WithValue(ctx, CtxKeyRequestID, requestID)
+	ctx = context.WithValue(ctx, CtxKeyWorkerID, workerID)
+	ctx = context.WithValue(ctx, CtxKeyStartTime, time.Now())
+	return ctx, cancel
+}
+
+// Helper functions to get values from context
+
+// GetURLFromContext retrieves the URL from the context
+func GetURLFromContext(ctx context.Context) string {
+	if url, ok := ctx.Value(CtxKeyURL).(string); ok {
+		return url
+	}
+	return ""
+}
+
+// GetHostFromContext retrieves the host from the context
+func GetHostFromContext(ctx context.Context) string {
+	if host, ok := ctx.Value(CtxKeyHost).(string); ok {
+		return host
+	}
+	return ""
+}
+
+// GetRequestIDFromContext retrieves the request ID from the context
+func GetRequestIDFromContext(ctx context.Context) string {
+	if id, ok := ctx.Value(CtxKeyRequestID).(string); ok {
+		return id
+	}
+	return ""
+}
+
+// GetWorkerIDFromContext retrieves the worker ID from the context
+func GetWorkerIDFromContext(ctx context.Context) int {
+	if id, ok := ctx.Value(CtxKeyWorkerID).(int); ok {
+		return id
+	}
+	return -1
+}
+
+// GetStartTimeFromContext retrieves the start time from the context
+func GetStartTimeFromContext(ctx context.Context) time.Time {
+	if startTime, ok := ctx.Value(CtxKeyStartTime).(time.Time); ok {
+		return startTime
+	}
+	return time.Time{}
+}
+
+// GetComponentFromContext retrieves the component name from the context
+func GetComponentFromContext(ctx context.Context) string {
+	if component, ok := ctx.Value(CtxKeyComponent).(string); ok {
+		return component
+	}
+	return ""
+}
+
+// ContextWithComponent adds or updates the component name in the context
+func ContextWithComponent(ctx context.Context, component string) context.Context {
+	return context.WithValue(ctx, CtxKeyComponent, component)
+}