feat(portfolio): complete RESOURCE-WP-0003 T06 optimization cases and T07 reporting

T06: optimization-case schema, fail-closed evaluator, cadence and decision
template. Every option including the baseline must present all ten decision
fields; one unknown blocks the comparison. Validated on the storage case
(Hetzner computes and loses to Scaleway by EUR 29.14/month on operator labour;
Host Europe blocks on four named gaps) and on the non-storage reef-railiance
k3s rightsizing case (low utilization is real, but nothing is costable while
the railiance01 price is unknown).

T07: portfolio report over coverage, lifecycle, utilization, cost, renewals,
risks, open cases, and next actions, derived only from committed evidence.
Portfolio spend is reported null rather than as a partial sum, unattributed
cost is a named list rather than a spread, and unmeasurable resources are
reported rather than dropped.

RESOURCE-WP-0003 is finished; both cases remain blocked_on_evidence against
live delegated records in other repositories. RESOURCE-WP-0002 is untouched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/forecast-actual-control.md

@@ -0,0 +1,123 @@
+# Forecast-to-actual resource control
+
+## Why the €2.89, €5.14, €62.89, and €65.14 figures differ
+
+They describe two volumes and two cost scopes:
+
+| Figure | Stored volume | Scope | Calculation |
+| --- | ---: | --- | --- |
+| €2.89 | 180 GB | infrastructure only | 180 × €0.01606 |
+| €62.89 | 180 GB | infrastructure + internal labor | €2.89 + 1 h × €60 |
+| €5.14 | 320 GB | infrastructure only | 320 × €0.01606 |
+| €65.14 | 320 GB | infrastructure + internal labor | €5.14 + 1 h × €60 |
+
+The older €62.89 estimate was not “storage without elastic cost”; it already
+included the €60 monthly operator allowance. The normalized table introduced a
+different stored volume and showed infrastructure separately. Future reports
+must always label both `stored_gb` and cost scope.
+
+## Control records
+
+A forecast is a timestamped, immutable record of what was believed at decision
+time. The initial base forecast is
+`data/forecasts/platform-audit-storage-scaleway-base-2026-08.json`. Do not edit
+it after actual evidence exists. If assumptions change, create a new forecast
+with a new creation date and retain the prior one so forecast accuracy remains
+auditable.
+
+After every billing month, record a technical `usage_observation` under
+`data/actuals/`. Authoritative booked financial facts come from fin-hub and
+are joined by reference; resource-control does not originate a second booked
+actual.
+The required cost and usage proxies are:
+
+- database size and provider stored bytes;
+- WAL volume;
+- write and read requests;
+- restore-test egress;
+- infrastructure invoice cost;
+- internal operations hours and valued labor cost;
+- total attributable cost;
+- backup success, maximum observed RPO, and restore RTO when measured.
+
+Provider stored bytes are intentionally distinct from logical database size.
+They expose base-backup retention, WAL, compression, versioning, incomplete
+multipart uploads, and lifecycle behavior. Invoice cost is distinct from the
+provider's usage estimator and must reconcile to non-secret billing evidence.
+
+## Error calculation and review
+
+`make variance ACTUAL=data/actuals/YYYY-MM.json` reports signed error and
+absolute percentage error for each numeric proxy. Initially review rather than
+automatically rewrite assumptions:
+
+- investigate infrastructure cost error above 10%;
+- investigate stored-byte or WAL error above 20%;
+- investigate any unplanned egress or request-class charge;
+- investigate labor error above 1 hour or 25%;
+- investigate every backup failure, RPO breach, or restore-RTO regression.
+
+After three comparable months, calculate mean absolute percentage error by
+proxy and recalibrate the next forecast. Avoid MAPE where the forecast is zero;
+use absolute error and explain the new activity instead. Separate forecast
+error from price variance: a bill can differ because usage was wrong, the rate
+changed, tax/discount treatment differed, or an unmodeled SKU appeared.
+
+Quarterly provider comparison should use the latest actual trailing three
+months, the next 12-month forecast, one monthly restore, an exit event, and
+observed—not aspirational—operator labor.
+
+## General portfolio control record
+
+The storage-specific v0.1 observation remains valid for the backup procurement
+case. New portfolio controls use
+`schemas/resource-control-cycle.schema.json`, whose resource-specific
+`usage_proxies` allow the same comparison mechanism to cover storage, VMs or
+cluster compute, shared platform services, managed services, and future
+resource types without pretending they share the same utilization unit.
+
+Each record separates:
+
+- provisioned and used capacity, with a fixed, elastic, or hybrid model;
+- infrastructure, internal labor, and external labor cost;
+- booked financial facts, referenced rather than copied from fin-hub;
+- allocation method, driver, version, and unattributed residual;
+- service constraints and their units;
+- low/base/high forecast scenario or observed actual;
+- evidence and uncertainty.
+
+Forecast records are append-only. A changed forecast receives a new
+`record_id`, creation time, and `revision_of` reference. Actuals must name the
+exact original `forecast_ref`; a later revision must never replace the
+decision-time baseline when measuring forecast error.
+
+Run a generic comparison with:
+
+```sh
+make control-cycle FORECAST=examples/control-cycle/storage-forecast.json \
+  ACTUAL=examples/control-cycle/storage-actual.json
+```
+
+The examples cover storage, `reef-railiance` cluster compute, and the shared
+`apps-pg` service. Their numbers are illustrative contract fixtures, not booked
+facts. Operational records replace their evidence references after the owner
+workplans publish observations.
+
+## Variance attribution
+
+Every material variance is assigned to one of six controlled categories:
+
+- `demand`: the amount of consumed service differed;
+- `provider_price`: rate, discount, tax, currency, or billed SKU differed;
+- `allocation`: a shared-cost driver or attribution changed;
+- `labor`: internal or external effort differed;
+- `model`: a formula, assumption, capacity behavior, or omitted component was
+  wrong;
+- `data_quality`: evidence is missing, late, inconsistent, or uses a different
+  unit.
+
+The comparator defaults usage differences to demand, infrastructure cost to
+provider price, and labor fields to labor, while preserving explicit
+attribution supplied with the actual. Missing proxies and unit mismatches fail
+closed as data-quality errors. Attribution explains an error; it does not
+rewrite the forecast.