Notion connector: project-knowledge "Search Resources or Paste URL" field surfaces only internal connector docs and cannot search or resolve any user page

### What happened?

The Notion connector presents a "Search Resources or Paste URL" field for adding content to project knowledge. In practice the field cannot surface, search, or resolve any Notion page or database in the user's workspace. Both the search function and the paste-URL function fail. The only items the field ever lists are two resources that are not part of the user's workspace: **"Enhanced Markdown Specification"** and **"View Configuration DSL"**, which are the Notion MCP server's internal documentation resources. The connector itself is authorized and fully functional for tool-based access in normal chats.

### What did you expect to happen?

Search returns matching pages/databases from the workspace; selecting one attaches it to project knowledge. Pasting a valid Notion page URL resolves and attaches that page.

### Steps to reproduce

1. Connect and authorize the Notion connector.
2. Open a Project → Files → "+" → Add Content → select Notion.
3. In the "Search Resources or Paste URL" field: (a) type the title of a known Notion page, and (b) separately, paste a Notion page URL.

### Area

Resource Handling

### MCP Server (if applicable)

Notion (mcp.notion.com)

### Error messages or logs

```shell
**Search:** typing any page title returns no workspace pages. The result list only ever shows two entries, "Enhanced Markdown Specification" and "View Configuration DSL", regardless of query.

**Paste URL, https forms:** every standard form returns `failed to resolve URL. Make sure MCP server supports this URL.` Tested: `https://www.notion.so/`, `https://www.notion.so/Title-`, `...?pvs=4`, `...?pvs=1`, `https://notion.so/` (no www), dashed-UUID form, and bare id with no scheme.

**Paste URL, notion:// deeplink:** `notion://www.notion.so/` returns no error, but also no result. Nothing attaches. The divergence from the https forms suggests scheme-dependent handling.
```

### Additional context

_No response_