Agent Skills: lisa-sentry-access

Vendor-neutral access layer for Sentry. Sentry-oriented skills MUST delegate through this skill rather than calling Sentry MCP tools, sentry-cli, or REST directly. Per the credential-substrate-precedence contract, resolves SENTRY_AUTH_TOKEN (REST, or sentry-cli authenticated from the same token) first when present and identity-matched to the configured org/project, then falls back to the Sentry MCP.