fix(people): detach authenticated principal scalar evidence from caller aliases #330

Finding

Canonical People AuthenticatedPrincipal validated tenant_record_id with isinstance(..., UUID) and then retained the caller-owned UUID object unchanged. Python uuid.UUID instances can be altered through low-level object.__setattr__, so a caller retaining the original UUID alias could change the principal tenant after construction. The predecessor also evaluated .int sentinel equality before proving that the retained payload was the exact built-in int; a forged exact-UUID payload could therefore execute caller-defined equality behavior during validation.

The constructor also accepted str subclasses for actor_reference / scope codes and frozenset subclasses for granted_scope_codes, allowing behavior-bearing retained values across the authorization boundary. This is a concrete realization of the retained-authority/scalar invariants already recorded by the canonical product-technical gap baseline; no competing baseline edit is needed.

Repair lineage

PR #55 is the canonical owner.

• Test-first d0799709d0d5541ae09e672919154317de2cf938 adds regressions requiring: forged UUID .int payload rejection before equality behavior; tenant UUID detachment from a caller alias; exact built-in actor/scope strings; and rejection of frozenset subclasses before subclass iteration.
• Causal repair 0853605c284cb6e9d76f14bf1e0366ffee6e5d95 captures UUID .int once, requires exact built-in int within the 128-bit range before sentinel equality, reconstructs an owned UUID, requires exact built-in str for actor/scope evidence, and requires exact built-in frozenset before iteration. Purpose authorization remains outside the principal.

The public principal fields and existing purpose separation are preserved; no Keyverse/policy logic moved into the value object.

Current evidence boundary

#55 exact head is 0853605c284cb6e9d76f14bf1e0366ffee6e5d95, direct to protected develop@eb9757f8649aaad026a9865508d9aad50c1a7a4f, Draft and mergeable. Fresh exact-head workflows have materialized:

• Foundation CI 34838670623 — queued
• Security Scan 34838670519 — queued
• SAST Semgrep 34838670492 — queued
• CodeQL PR 34838670493 — queued

No predecessor GREEN/review transfers and no hosted GREEN is claimed while these remain queued. Employment descendants were ordinary-forward restacked without force-push: #149 f7595aa8c4850bfaf69787ed4016c4bb797b8182, #155 f988e1effe612170a37445e7577877fc46a9b2e0, #156 e2f6327202688d72430fcbd86be7b702c41a44f1.

Keep #330 open through exact-head acceptance and protected integration.