Return Knowhere MCP results as tagged text

[suguanYang]

Summary

• Replace Knowhere MCP JSON/structuredContent tool results with single tagged text payloads rooted at .
• Surface storageRoot, chunkPath, storageLocation, pageAssets, and assetUrl guidance directly in text output for read/search flows.
• Update MCP response-contract docs, exact MCP tests, and add a patch changeset for @ontos-ai/knowhere-mcp.

Verification

• pnpm --filter @ontos-ai/knowhere-mcp test -- --run
• pnpm --filter @ontos-ai/knowhere-mcp typecheck
• pnpm --filter @ontos-ai/knowhere-mcp lint
• git diff --check

Lint completed with existing console warnings in packages/mcp/src/stdio.ts and no errors.

Checklist

• Tests were added or updated when behavior changed
• Public docs or examples were updated when needed
• A changeset was added when a release should be published