feat: guard tool coverage for GitHub MCP server + proxy router expansion

[lpcox]

Problem

Cross-referencing all tool names from github/github-mcp-server source against the guard's tool_rules.rs revealed 22 read tools falling through to the default _ => case, which inherits empty labels. This means these tools had no integrity or secrecy labeling, causing them to either be filtered at any min-integrity threshold or leak private data without secrecy tags.

Additionally, the proxy router had gaps where Actions, discussions, user, and notification endpoints either fell through to a generic get_file_contents fallback (wrong security labels) or were blocked entirely.

Changes

Guard: New tool coverage in tool_rules.rs (22 read tools)

Category	Tools	Secrecy	Integrity	Rationale
Actions	get_job_logs	secret	approved	Logs may contain leaked env vars/tokens
Context	get_me	private:user	project:github	User PII (email, profile)
Context	get_teams, get_team_members	private:user	project:github	Org structure is sensitive
Discussions	list_discussions, get_discussion	repo visibility	approved	User content, similar to issues
Discussions	get_discussion_comments	repo visibility	approved	User content, similar to issue comments
Discussions	list_discussion_categories	repo visibility	approved	Maintainer-managed metadata
Gists	list_gists, get_gist	private:user	unapproved	User content, no repo-level trust signal
Git	get_repository_tree	repo visibility	approved	Repo metadata
Labels	list_label	repo visibility	approved	Maintainer-managed metadata
Notifications	list_notifications, get_notification_details	private:user	none (empty)	References external content of unknown trust
Projects	projects_list, projects_get	[]	approved:owner	New canonical project tool names
Repos	list_starred_repositories	private:user	project:github	Reveals user preferences/interests
Search	search_orgs	[]	project:github	Public GitHub-controlled metadata
Security	list_global_security_advisories, get_global_security_advisory	[]	project:github	Published GHSA CVE data
Security	list_repository_security_advisories, list_org_repository_security_advisories	private:repo	approved	May contain embargoed vulnerability info

Also updated tools.rs: added actions_run_trigger, projects_write, add_reply_to_pull_request_comment to write operations.

Guard: Unit tests (37 new tests)

Every new tool has corresponding tests for label_resource and label_response.

Guard: Compiler warning fix

Gated has_approval_label with #[cfg(test)] (only used in tests).

Proxy: 22 new REST routes + 5 GraphQL patterns

• Actions: get workflow/run/job, workflow-specific runs, attempt jobs/logs, artifacts, caches, secrets, variables, environment config
• Discussions: list, single, comments (REST + GraphQL)
• User: /user, /user/keys|ssh_signing_keys|gpg_keys (REST), viewer {} (GraphQL)
• Notifications: /notifications
• Check runs: /commits/{sha}/check-runs|check-suites
• Org-scoped: /orgs/{org}/actions/secrets|variables
• Organization: organization() GraphQL

Valid integrity levels: merged > approved > unapproved > none > blocked

[Copilot]

Pull request overview

This PR adjusts the guard label helper API surface so that has_approval_label is only compiled and re-exported in test builds, addressing a compiler warning from non-test builds.

Changes:

• Gate helpers::has_approval_label behind #[cfg(test)] so it’s only compiled for unit tests.
• Update labels::mod re-exports to only expose has_approval_label in test builds.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
guards/github-guard/rust-guard/src/labels/mod.rs	Removes unconditional re-export and re-exports has_approval_label only under #[cfg(test)].
guards/github-guard/rust-guard/src/labels/helpers.rs	Marks has_approval_label as #[cfg(test)] to prevent non-test compilation.

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