refactor(agent): extract agent pool and HTTP utilities to dedicated package

Moved non-agent-specific logic from agent/pkg/agent/ to internal/agentpool/:
- pool.go: Agent pool management (Get, Add, Remove, List, Iter, etc.)
- http_requests.go: HTTP utilities (health checks, forwarding, websockets, reverse proxy)
- agent.go: Agent struct with HTTP client management

This separates general-purpose pool management from agent-specific configuration,
improving code organization and making the agent package focused on agent config only.

internal/route/route.go

@@ -16,7 +16,7 @@ import (
 
 	"github.com/docker/docker/api/types/container"
 	"github.com/rs/zerolog/log"
-	"github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/godoxy/internal/agentpool"
 	config "github.com/yusing/godoxy/internal/config/types"
 	"github.com/yusing/godoxy/internal/docker"
 	"github.com/yusing/godoxy/internal/homepage"
@@ -95,7 +95,7 @@ type (
 
 		provider types.RouteProvider
 
-		agent *agent.AgentConfig
+		agent *agentpool.Agent
 
 		started      chan struct{}
 		onceStart    sync.Once
@@ -154,10 +154,10 @@ func (r *Route) validate() gperr.Error {
 		}
 		var ok bool
 		// by agent address
-		r.agent, ok = agent.GetAgent(r.Agent)
+		r.agent, ok = agentpool.Get(r.Agent)
 		if !ok {
 			// fallback to get agent by name
-			r.agent, ok = agent.GetAgentByName(r.Agent)
+			r.agent, ok = agentpool.GetAgent(r.Agent)
 			if !ok {
 				return gperr.Errorf("agent %s not found", r.Agent)
 			}
@@ -511,7 +511,7 @@ func (r *Route) Type() route.RouteType {
 	panic(fmt.Errorf("unexpected scheme %s for alias %s", r.Scheme, r.Alias))
 }
 
-func (r *Route) GetAgent() *agent.AgentConfig {
+func (r *Route) GetAgent() *agentpool.Agent {
 	if r.Container != nil && r.Container.Agent != nil {
 		return r.Container.Agent
 	}