Generate contract types, pin fixtures to spec, add build and ADRs

Completes FLUID-WP-0002. The record types in internal/contract are
generated from schemas/ by a dependency-free generator; fixtures
transcribed from the spec's worked examples validate against those
schemas and round-trip through the generated types with
DisallowUnknownFields, so a spec change that misses the schemas fails
CI rather than drifting silently.

Adds identifier prefix helpers, Makefile, GitHub Actions, and five ADRs
recording the Go choice, out-of-process attachment, the wire contract as
boundary, the evidence store, and revision identity.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014KmVxhJ35tCo7rE7UnLwWu

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 1116572@bnt-lap001
Assistant-Session: 8ba9bb93-a72a-4883-b189-2499cce5c400

conformance/fixtures/revision.yaml

@@ -0,0 +1,134 @@
+fluid_revision:
+  schema_version: "0.1"
+
+  id: "R-000221"
+  interface_id: "customer-finance-api"
+
+  revision_number: 22
+  parent_revision: "R-000220"
+
+  state: "CANDIDATE"
+
+  created_at: "2026-09-04T13:10:00Z"
+  created_by:
+    type: "daimon"
+    id: "fluid-daimon/customer-finance-api"
+
+  contract:
+    type: "openapi"
+    version: "3.1"
+    artifact_ref: "artifact:openapi/customer-finance-api/r22"
+    digest: "sha256:3b1f9c2e7a4d8b6051e2c9f0a7d4b83e15c6f2a9d0b7e4c1836a5f2d9c0b7e41"
+
+  implementation:
+    artifact_ref: "artifact:adapter/customer-finance-api/r22"
+    source_ref: "git:9f4c2ab"
+    build_ref: "build:8871"
+    digest: "sha256:3b1f9c2e7a4d8b6051e2c9f0a7d4b83e15c6f2a9d0b7e4c1836a5f2d9c0b7e41"
+
+  interface_evolution_intent:
+    version: "IEI-7"
+    artifact_ref: "artifact:intent/customer-finance-api/IEI-7"
+
+  originating_hypotheses:
+    - "H-000184"
+
+  backend_requirements: []
+
+  compatibility:
+    class: "BACKWARD_COMPATIBLE"
+    breaking_changes: []
+    deprecations: []
+    supersedes: []
+    compatibility_evidence_refs:
+      - "test:compat-suite-775"
+
+  adaptation_classes:
+    - "contract"
+
+  verification:
+    status: "PASSED"
+    test_refs:
+      - "test:unit-12081"
+      - "test:contract-8821"
+      - "test:security-610"
+      - "test:compat-suite-775"
+    security_check: "PASSED"
+    policy_check: "PASSED"
+
+  complexity:
+    before:
+      surface_area: 41
+      operation_count: 39
+    after:
+      surface_area: 42
+      operation_count: 40
+    delta_score: 0.18
+    budget_status: "WITHIN_BUDGET"
+
+  deployment:
+    environments:
+      - name: "production"
+        started_at: "2026-09-05T08:00:00Z"
+        routing_policy_ref: "route-policy:rp-118"
+    current_exposure:
+      traffic_share: 0.28
+      cohorts:
+        - "partner-integrations"
+        - "coding-agents"
+
+  fitness:
+    baseline_revision: "R-000220"
+    measurement_window:
+      start: "2026-09-05T08:00:00Z"
+      end: null
+    metrics:
+      requests_per_completed_task:
+        baseline: 2.7
+        current: 1.15
+        target: 1.2
+      p95_latency_ms:
+        baseline: 300
+        current: 302
+        guardrail: 315
+      error_rate:
+        baseline: 0.008
+        current: 0.007
+
+  adoption:
+    eligible_consumers: 412
+    active_consumers: 119
+    adoption_rate: 0.289
+    retained_adoption_rate: null
+
+  economics:
+    build_cost: 38.20
+    experiment_cost_to_date: 12.40
+    currency: "EUR"
+
+  promotion:
+    eligible: true
+    recommended_state: "STABLE"
+    recommendation_reason: >
+      Target fitness reached with no guardrail violations.
+    authorized_by: null
+    authorized_at: null
+
+  rollback:
+    supported: true
+    target_revision: "R-000220"
+    procedure_ref: "runbook:rollback-r22"
+
+  provenance:
+    decision_refs:
+      - "D-2811"
+    experiment_refs:
+      - "E-000093"
+    telemetry_refs:
+      - "telemetry:invoice-pattern-2026w36"
+
+  audit:
+    immutable_event_refs:
+      - "EV-990221"
+      - "EV-990244"
+      - "EV-990281"