Make status and doctor observation-safe for non-enrolled repositories

[StatPan]

Goal

Let Gira inspect any GitHub repository without treating absent Gira metadata as a product failure.

Scope

• Consume the explicit operation-mode/policy contract.
• Classify status and doctor findings as environment, provider observation, or managed-policy findings.
• Make next-step output policy-aware and non-mutating by default.
• Add JSON provenance and regression fixtures for non-enrolled repositories.

Non-goals

• Do not alter ticket start, PR, or finish gating.
• Do not add a new root command or auto-enroll repositories.

Acceptance Criteria

• In observation mode, missing Gira labels and milestones are advisory rather than doctor failure.
• Status does not prescribe managed lifecycle actions for an unenrolled repository.
• JSON distinguishes mode, policy source, enforced findings, and advisories.
• Managed behavior is retained by regression tests.

Doctor Impact

This ticket changes doctor and status classification only; it must preserve strict managed-policy findings where that policy is explicitly enabled.

Expected Delivery

• One focused PR after the shared policy-contract ticket is available.

Verification

• Focused Go tests plus go test ./... before PR.

[StatPan]

Blocker

Depends on #936 for the explicit operation-mode and delivery-policy resolver. This ticket remains ready but should start only from that shared contract to avoid duplicating configuration semantics.

Context:

• Ticket: Make status and doctor observation-safe for non-enrolled repositories #935
• Status: Ready
• Linked PR: none
• Blockers: missing_linked_pr
• Next: gira ticket start --repo StatPan/gira --ticket 935 --apply