Rename "Resources" selector in FlowFuse Expert (Insights mode) to reduce MCP terminology confusion

## Problem

The server selection button in FlowFuse Expert's Insights mode is currently labeled in a way that leads users to believe they are selecting individual capabilities (resources, tools, prompts), when in reality they are selecting MCP servers. This causes confusion, especially for users who are familiar with MCP concepts and expect finer-grained control.

Additionally, MCP terminology itself is overloaded and confusing for end users. "MCP" is used interchangeably to refer to servers, clients, tools, resources, and prompts depending on context — making it difficult for users to build a clear mental model.

## Context from discussion

- A contributor was confused about the purpose of RBAC and annotations in the MCP Tool node, unclear whether these applied to FlowFuse Expert, external agents, or both.
- After clarification: RBAC rules are enforced when using FlowFuse Expert in Insights mode (scoped to application permissions), but not enforceable for external agents/clients connecting to FlowFuse-hosted MCP servers.
- The "Resources" label was originally chosen because the intent was to select resources for a query, with a future vision of finer-grained capability selection (e.g., toggling individual tools/resources per server). However, the current implementation only allows server-level selection.

## Potential Solutions

1. **Rename the server selector button** — Replace the current label with something less ambiguous. Candidates discussed:
- **"Include..."** — pragmatic, action-oriented (team favourite)
- "Add Context" — clear but potentially overlaps with "context" terminology
- "Tooling" — slightly better but still ambiguous
- Avoid "Resources" (overlaps with MCP terminology) and "Servers" (loses meaning for end users)

2. **Update the input placeholder text** — The current placeholder reinforces the confusion and should be updated to match the new terminology.

3. **Update the release blog** — The 2.25 release blog references the old terminology and should be updated.

## Additional consideration

- The two modes of FlowFuse Expert (Support and Insights) should remain separate — they serve fundamentally different purposes ("ask about Node-RED/FlowFuse" vs. "get insights on your flows/data").
- Future consideration: intent detection to suggest mode switching when a user's question better fits the other mode. **Not in scope for this issue.**