Canonical sandbox test-data table (zero-auth)

Machine-readable directory of every sandbox test fixture: the single source docs and agents link to instead of a hand-kept appendix. Enumerates the reserved write-side test orgs (999000001-005, the only orgs /api/v1/sandbox/actions/execute accepts as a successful filing), the Altinn acting-capacity scenario orgs, the MOD-11-valid realistic graph, the difficult-company personas (999770-series: realistic, internally-consistent companies for pre-production agent testing: bankruptcy in progress, voluntary liquidation, VAT deregistered, disputed signatur, degraded data, merger pair, NUF branch, dormant, and more, each with a difficulty descriptor and an expected verdict block), the single public-sandbox org, the four reserved error orgs (org → forced error code), all eight ?simulate_error= tokens, the ?simulate_latency= / ?mock_date= query knobs, and the magic VAT values that force MVA-melding filing outcomes. The execute block also carries the write-loop contract agents otherwise discover by 400 round-trip: execute.request_body (the JSON field is action, not action_type; approval_token rides in the body), execute.required_headers (Idempotency-Key is mandatory; Authorization recommends the synthetic apier_sandbox_test_<suffix> bearer, noting that a real key also authenticates but is unnecessary because the sandbox never reaches a government upstream), and execute.sandbox_clock (pinned_at, local_time, timezone: Europe/Oslo, and a note, all derived from the single pinned sandbox instant that ?mock_date= overrides on the write-side routes). Zero-auth (Category A discovery), per-IP rate-limited, deterministic except _meta.response_timestamp. Every value listed here reproduces its documented behaviour on the sandbox surface.