T-15: Logging infrastructure with os.Logger

[kirich1409]

Description

Create MacApp/Packages/GitHubIntegration/Sources/GitHubIntegrationClient/GitHubLogger.swift:

import os

public enum GitHubLog {
    public static let subsystem = "com.relay.github"
    public static let auth     = Logger(subsystem: subsystem, category: "auth")
    public static let api      = Logger(subsystem: subsystem, category: "api")
    public static let polling  = Logger(subsystem: subsystem, category: "polling")
}

Usage rules (documented in file-level docstring)

• auth — sign-in/out events, token validation, state mismatch. Never log token, code, code_verifier, state values. Use privacy: specifier for user-data placeholders.
• api — HTTP method + path + status (no body, no Authorization header). Redact query tokens if any.
• polling — poll tick start/end (debug), worktree count (debug), rate-limit remaining (notice when low).
• Errors: logger.error("...", privacy: .private) for user-data placeholders.
• Severity map: debug (verbose trace), info (normal flow), notice (warning), error (recoverable), fault (programming bug).
• print(...) — forbidden in production code paths. Document as project-wide rule in CLAUDE.md (T-16) or as SwiftLint rule.

Pilot usage

Demonstrate usage in GitHubClient.perform(...) (T-5) and GitHubAuthService.signIn (T-7) — any interim print replaced with appropriate GitHubLog category.

Spec reference

See swarm-report/github-integration-decomposition.md#t-15.

Relationships

• Parent issue: EPIC: GitHub Integration MVP (read-only CI status + popover + OAuth) #214
• Blocked by: T-2
• Blocks: T-7 (uses GitHubLog.auth)
• Related: T-5 (uses GitHubLog.api), T-8b (uses GitHubLog.polling)

Acceptance criteria

• GitHubLog enum compiles; three categories available
• File-level docstring contains redaction rules verbatim
• Pilot usage integrated (T-5 or a minimal DemoLogging.swift if T-5 not yet merged)
• log stream --subsystem com.relay.github shows expected events in smoke (deferred to T-13 manual verification)
• No print(...) calls introduced in this PR

Complexity

S

Suggested agent

developer-workflow:swift-engineer

Module / Layer

GitHubIntegrationClient / Infrastructure