HITL tool permissions: tidy verbose comments from review

[andypalmi]

Repo: FlowFuse/flowfuse
Refs: #7639 (feat: human-in-the-loop tool permissions), FlowFuse/product#421

Context

Review of #7639 flagged several over-long inline comments that were agreed to be trimmed in a follow-up. This groups the trivial comment and cleanup nits into one fast, zero-behaviour-change PR.

What

1. forge/ee/routes/expert/index.js (the /mcp/tools handler doc block, currently around line 588): shorten the multi-line description to a couple of lines. Keep the key facts: it returns the merged catalog (flow-building proxied from the agent's /mcp/flow-tools, plus curated platform tools), with a hash for change detection.
2. forge/ee/routes/expert/index.js (curatePlatformTool doc block, around line 17): shorten. Keep that it maps a platform tool wire definition to a catalog entry and derives read/write/delete class from the MCP annotations.
3. forge/ee/routes/expert/index.js (catch block, around line 658): remove the stale TODO: decide with the team whether this belongs on the branch. The feature is merged, so the decision is made. Keep the substantive comment explaining why an upstream 401/403 must not be forwarded as our own 401 (the SPA axios interceptor treats any 401 as session expiry and logs the user out).
4. frontend/src/components/elements/ToggleButtonGroup.vue (size prop, around line 65): shorten the comment to just note the accepted values (passed through to ff-button).

Acceptance criteria

• Comments trimmed as above, no logic changes.
• Lint and build green.

Size

~1h.