Document Copilot Spaces PAT requirements

[Bestra]

Summary

Document the authentication constraints for the remote-only Copilot Spaces tools in the README. The new note explains why fine-grained PAT users can still see the tools, but still need the right org installation, organization_copilot_spaces: read, and repo access for repo-backed resources.

Why

The README currently lists get_copilot_space and list_copilot_spaces without explaining why a fine-grained PAT might still see those tools but fail when it tries to use them. This is a small docs followup so the org-installed token requirement and the repo-backed-resource visibility behavior are easier to discover.

What changed

• Added an authentication note to the remote-only Copilot Spaces section in README.md.
• Called out that fine-grained PATs are not hidden by classic PAT scope filtering.
• Documented the org installation + organization_copilot_spaces: read requirement and the repo-backed-resource access requirement.

MCP impact

• No tool or API changes
• Tool schema or behavior changed
• New tool added

Prompts tested (tool changes only)

• Not applicable; docs-only change.

Security / limits

• No security or limits impact
• Auth / permissions considered
  • This PR only documents the existing Copilot Spaces auth requirements for fine-grained PATs.
• Data exposure, filtering, or token/size limits considered
  • The README now calls out that org-owned spaces with repo-backed resources may be hidden if the token lacks repo access.

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Lint & tests

• Linted locally with ./script/lint
• Tested locally with ./script/test

Docs

• Not needed
• Updated (README / docs / examples)

[Copilot]

Pull request overview

Updates the documentation for the remote-only Copilot Spaces toolset to clarify why fine-grained PAT users may still see the tools listed but encounter authentication/authorization failures when invoking them.

Changes:

• Added an “Authentication note” to the Copilot Spaces section describing fine-grained PAT visibility vs usability.
• Documented the org installation + organization_copilot_spaces: read requirement for org-owned spaces.
• Documented that repo-backed resources may require additional repository access or the space can appear “not found”.

Show a summary per file

File	Description
README.md	Adds an authentication/permissions note for remote-only Copilot Spaces tools to reduce confusion for fine-grained PAT users.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0