refactor: add marketplace bridge and gateway market APIs

[h1177h]

背景

本次调整将云端市场相关逻辑收敛到 marketplace bridge，避免 gateway、runtime、agent 工具层分别直接处理 registry、安装策略、绑定和 job 状态。

主要改动

• 新增 marketplace bridge，统一封装搜索、详情、版本、安装计划、安装、升级、卸载、绑定、jobs、events。
• markettools 改为通过 bridge 调用，不再直接创建 policy/install use case。
• runtime 只保留安装/绑定/卸载后的本地集成与刷新 hook。
• gateway 市场读写 API 统一走 bridge，包括 artifacts、install、upgrade、uninstall、jobs、bindings、events、refresh。
• agent 增加轻量 capability planner，用于在缺少本地能力时暴露 marketplace 搜索工具，并在确认场景暴露安装/绑定工具。
• 补充 bridge、gateway market API、capability planner、prompt 相关测试。

验证

• go test ./...

[fennoai]

I found 2 issues in the refactor: uninstall leaves runtime-integrated artifacts behind, and binding normalization can panic when the runtime is unavailable.

[codecov]

Codecov Report

❌ Patch coverage is 63.29114% with 435 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pkg/marketplace/bridge/bridge.go	60.86%	89 Missing and 46 partials ⚠️
pkg/capability/agents/agent.go	62.36%	64 Missing and 6 partials ⚠️
pkg/gateway/gateway_market_install_api.go	43.15%	36 Missing and 18 partials ⚠️
pkg/runtime/market_integration.go	48.54%	35 Missing and 18 partials ⚠️
pkg/gateway/gateway_market_bindings_api.go	65.92%	30 Missing and 16 partials ⚠️
pkg/capability/agents/capability_planner.go	76.13%	34 Missing and 8 partials ⚠️
pkg/gateway/gateway_market_store.go	54.54%	9 Missing and 6 partials ⚠️
pkg/gateway/gateway_market_artifacts_api.go	50.00%	8 Missing and 1 partial ⚠️
pkg/capability/markettools/marketplace.go	76.19%	2 Missing and 3 partials ⚠️
pkg/capability/agents/prompt/prompt.go	90.69%	2 Missing and 2 partials ⚠️
... and 1 more

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