feat: sdk NoMemory/Cleaner + example build fixes

- sdk/plugin.go: ToolDef adds NoMemory/Cleaner fields
- sdk/plugin_test.go: unit tests for NoMemory/Cleaner
- all example plugins: NoMemory/Cleaner annotated for each tool
- plugindev/templates.go: template shows NoMemory/Cleaner pattern
- plugindev/cmd_build.go: fix ensureGoMod, buildBundle/buildTarget sdkPath param, NewPluginFactory
- example/go.mod: add external dependency declarations (chromedp, gofeed)
- add main.go stubs for all example plugins

example/ocr/plugin.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -38,6 +39,17 @@ func (p *Plugin) Start(s *sdk.PluginSDK) error {
 				"language":   map[string]interface{}{"type": "string", "description": "识别语言，默认 chi_sim+eng（中文简体+英文），可选 chi_sim / eng / chi_sim+eng"},
 			},
 		},
+		Cleaner: func(output string) string {
+			var r struct{ Text string }
+			if json.Unmarshal([]byte(output), &r) == nil && r.Text != "" {
+				return r.Text
+			}
+			var r2 struct{ Content string }
+			if json.Unmarshal([]byte(output), &r2) == nil && r2.Content != "" {
+				return r2.Content
+			}
+			return output
+		},
 	}, p.handleOcrImage)
 
 	log.Printf("[%s] plugin started", p.name)
@@ -128,7 +140,6 @@ func (p *Plugin) handleOcrImage(args map[string]interface{}) (interface{}, error
 	}, nil
 }
 
-
-func NewPlugin(name string, config map[string]interface{}) (sdk.Plugin, error) {
+func NewPluginFactory(name string, config map[string]interface{}) (sdk.Plugin, error) {
 	return &Plugin{name: name}, nil
-}
+}