Add approval evidence to sprint dry-runs

[StatPan]

Goal

Make gira sprint plan|start|close|rollover --dry-run --json emit stable schema versions and the shared gira-approval-plan/v1 approval evidence envelope so adapters can approve sprint state and rollover mutations from structured evidence.

Scope

• Add stable schema versions to sprint plan, start, close, and rollover JSON reports.
• Attach approval evidence only to sprint dry-run mutation reports and omit it from apply reports.
• Reconstruct matching dry-run/apply commands from report fields, including repo, iteration, capacity, committed/completed issues, spillover disposition, rollover reason, and target milestone.
• Include planned actions, blockers/warnings arrays, and post-apply verification strings for each sprint mutation family.
• Update the agent-kernel adapter contract gap text once sprint dry-runs are covered.

Acceptance Criteria

• Sprint dry-run JSON includes the appropriate schema_version and approval.schema_version: gira-approval-plan/v1.
• Approval evidence includes stable planned actions, blockers/warnings arrays, matching apply/dry-run commands, and post-apply verification.
• Apply JSON retains schema versions and omits dry-run approval evidence.
• Existing sprint lifecycle and rollover behavior stay compatible.

Expected Delivery

Open one implementation PR with focused tests for sprint report construction and CLI JSON output. Merge after checks pass.

Parent: #521

base_branch: main
base_source: branch_policy.default
branch_policy_mode: github-flow
target: default
work_branch: issue-627-add-approval-evidence-to-sprint-dry-runs

[StatPan]

Finish Receipt

• Finished at: 2026-05-23T07:10:27Z
• Ticket: Add approval evidence to sprint dry-runs #627 status=Done state=closed
• Linked PR: feat: Add approval evidence to sprint dry-runs #628 state=MERGED merged=true
• Checks: passed total=11 passing=11 pending=0 failing=0
• Review: unknown
• Evidence: closing_reference,branch_binding,checks
• AI Delivery Telemetry: not_required
• Label changes: add=status:done remove=status:in-review
• Warnings: missing_acceptance_criteria
• Next: ticket is done