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

internal/contract/revision_descriptor_gen.go

@@ -0,0 +1,215 @@
+// Code generated by tools/schemagen. DO NOT EDIT.
+// Source: schemas/. Regenerate with `make generate`.
+
+package contract
+
+type RevisionContractType string
+
+const (
+	RevisionContractTypeOpenapi    RevisionContractType = "openapi"
+	RevisionContractTypeGraphql    RevisionContractType = "graphql"
+	RevisionContractTypeProtobuf   RevisionContractType = "protobuf"
+	RevisionContractTypeAsyncapi   RevisionContractType = "asyncapi"
+	RevisionContractTypeJsonschema RevisionContractType = "jsonschema"
+	RevisionContractTypeCustom     RevisionContractType = "custom"
+)
+
+// Valid reports whether v is a defined RevisionContractType.
+func (v RevisionContractType) Valid() bool {
+	switch v {
+	case RevisionContractTypeOpenapi, RevisionContractTypeGraphql, RevisionContractTypeProtobuf, RevisionContractTypeAsyncapi, RevisionContractTypeJsonschema, RevisionContractTypeCustom:
+		return true
+	}
+	return false
+}
+
+type RevisionContract struct {
+	Digest Digest `json:"digest" yaml:"digest"`
+
+	// Where the contract artifact can be fetched.
+	Source string               `json:"source,omitempty" yaml:"source,omitempty"`
+	Type   RevisionContractType `json:"type" yaml:"type"`
+}
+
+// Which interface evolution intent governs this revision. Required: a revision with
+// no governing intent cannot be audited.
+type RevisionIntent struct {
+	Digest  *Digest `json:"digest,omitempty" yaml:"digest,omitempty"`
+	Version string  `json:"version" yaml:"version"`
+}
+
+type RevisionPolicyCompatibility string
+
+const (
+	RevisionPolicyCompatibilityBackwardCompatible RevisionPolicyCompatibility = "backward_compatible"
+	RevisionPolicyCompatibilityForwardCompatible  RevisionPolicyCompatibility = "forward_compatible"
+	RevisionPolicyCompatibilityAdditive           RevisionPolicyCompatibility = "additive"
+	RevisionPolicyCompatibilityBehavioralChange   RevisionPolicyCompatibility = "behavioral_change"
+	RevisionPolicyCompatibilityBreaking           RevisionPolicyCompatibility = "breaking"
+	RevisionPolicyCompatibilityMigrationOnly      RevisionPolicyCompatibility = "migration_only"
+	RevisionPolicyCompatibilityInternalOnly       RevisionPolicyCompatibility = "internal_only"
+)
+
+// Valid reports whether v is a defined RevisionPolicyCompatibility.
+func (v RevisionPolicyCompatibility) Valid() bool {
+	switch v {
+	case RevisionPolicyCompatibilityBackwardCompatible, RevisionPolicyCompatibilityForwardCompatible, RevisionPolicyCompatibilityAdditive, RevisionPolicyCompatibilityBehavioralChange, RevisionPolicyCompatibilityBreaking, RevisionPolicyCompatibilityMigrationOnly, RevisionPolicyCompatibilityInternalOnly:
+		return true
+	}
+	return false
+}
+
+type RevisionPolicyPolicyCheck string
+
+const (
+	RevisionPolicyPolicyCheckPending RevisionPolicyPolicyCheck = "pending"
+	RevisionPolicyPolicyCheckPassed  RevisionPolicyPolicyCheck = "passed"
+	RevisionPolicyPolicyCheckFailed  RevisionPolicyPolicyCheck = "failed"
+)
+
+// Valid reports whether v is a defined RevisionPolicyPolicyCheck.
+func (v RevisionPolicyPolicyCheck) Valid() bool {
+	switch v {
+	case RevisionPolicyPolicyCheckPending, RevisionPolicyPolicyCheckPassed, RevisionPolicyPolicyCheckFailed:
+		return true
+	}
+	return false
+}
+
+type RevisionPolicySecurityCheck string
+
+const (
+	RevisionPolicySecurityCheckPending RevisionPolicySecurityCheck = "pending"
+	RevisionPolicySecurityCheckPassed  RevisionPolicySecurityCheck = "passed"
+	RevisionPolicySecurityCheckFailed  RevisionPolicySecurityCheck = "failed"
+)
+
+// Valid reports whether v is a defined RevisionPolicySecurityCheck.
+func (v RevisionPolicySecurityCheck) Valid() bool {
+	switch v {
+	case RevisionPolicySecurityCheckPending, RevisionPolicySecurityCheckPassed, RevisionPolicySecurityCheckFailed:
+		return true
+	}
+	return false
+}
+
+type RevisionPolicy struct {
+	Compatibility RevisionPolicyCompatibility `json:"compatibility" yaml:"compatibility"`
+	PolicyCheck   *RevisionPolicyPolicyCheck  `json:"policy_check,omitempty" yaml:"policy_check,omitempty"`
+	RollbackTo    *RevisionID                 `json:"rollback_to,omitempty" yaml:"rollback_to,omitempty"`
+	SecurityCheck RevisionPolicySecurityCheck `json:"security_check" yaml:"security_check"`
+}
+
+type RevisionRouting struct {
+	// Empty or absent means all cohorts are eligible.
+	EligibleCohorts []CohortID `json:"eligible_cohorts,omitempty" yaml:"eligible_cohorts,omitempty"`
+
+	// Ceiling the router enforces regardless of what a routing policy asks for.
+	MaxTrafficShare *UnitInterval `json:"max_traffic_share,omitempty" yaml:"max_traffic_share,omitempty"`
+}
+
+type RevisionRuntimeCircuitBreaker struct {
+	FailureThreshold *int64 `json:"failure_threshold,omitempty" yaml:"failure_threshold,omitempty"`
+	ResetAfterMS     *int64 `json:"reset_after_ms,omitempty" yaml:"reset_after_ms,omitempty"`
+}
+
+type RevisionRuntimeRetry struct {
+	BackoffMS   *int64   `json:"backoff_ms,omitempty" yaml:"backoff_ms,omitempty"`
+	MaxAttempts *int64   `json:"max_attempts,omitempty" yaml:"max_attempts,omitempty"`
+	RetryOn     []string `json:"retry_on,omitempty" yaml:"retry_on,omitempty"`
+}
+
+// Out-of-process attachment: the adapter is an upstream reached over the network,
+// so it may be implemented in any language.
+type RevisionRuntime struct {
+	CircuitBreaker *RevisionRuntimeCircuitBreaker `json:"circuit_breaker,omitempty" yaml:"circuit_breaker,omitempty"`
+	Digest         *Digest                        `json:"digest,omitempty" yaml:"digest,omitempty"`
+	Image          string                         `json:"image,omitempty" yaml:"image,omitempty"`
+	Retry          *RevisionRuntimeRetry          `json:"retry,omitempty" yaml:"retry,omitempty"`
+	TimeoutMS      *int64                         `json:"timeout_ms,omitempty" yaml:"timeout_ms,omitempty"`
+
+	// Base URL of the adapter process serving this revision.
+	Upstream string `json:"upstream" yaml:"upstream"`
+}
+
+type RevisionSignatureAlgorithm string
+
+const (
+	RevisionSignatureAlgorithmEd25519 RevisionSignatureAlgorithm = "ed25519"
+)
+
+// Valid reports whether v is a defined RevisionSignatureAlgorithm.
+func (v RevisionSignatureAlgorithm) Valid() bool {
+	switch v {
+	case RevisionSignatureAlgorithmEd25519:
+		return true
+	}
+	return false
+}
+
+// The router accepts only signed published descriptors (ArchitectureBlueprint.md
+// section 35). The signature covers the canonical form of this document with the
+// signature member removed.
+type RevisionSignature struct {
+	Algorithm RevisionSignatureAlgorithm `json:"algorithm" yaml:"algorithm"`
+	KeyID     string                     `json:"key_id" yaml:"key_id"`
+	SignedAt  *Timestamp                 `json:"signed_at,omitempty" yaml:"signed_at,omitempty"`
+	Value     string                     `json:"value" yaml:"value"`
+}
+
+// The router refuses to route to created, failed or retired revisions
+// (ArchitectureBlueprint.md section 5.3).
+type RevisionState string
+
+const (
+	RevisionStateCreated    RevisionState = "created"
+	RevisionStateVerified   RevisionState = "verified"
+	RevisionStateExperiment RevisionState = "experiment"
+	RevisionStateCandidate  RevisionState = "candidate"
+	RevisionStateStable     RevisionState = "stable"
+	RevisionStateDeprecated RevisionState = "deprecated"
+	RevisionStateRetired    RevisionState = "retired"
+)
+
+// Valid reports whether v is a defined RevisionState.
+func (v RevisionState) Valid() bool {
+	switch v {
+	case RevisionStateCreated, RevisionStateVerified, RevisionStateExperiment, RevisionStateCandidate, RevisionStateStable, RevisionStateDeprecated, RevisionStateRetired:
+		return true
+	}
+	return false
+}
+
+type Revision struct {
+	Contract RevisionContract `json:"contract" yaml:"contract"`
+	ID       RevisionID       `json:"id" yaml:"id"`
+
+	// Which interface evolution intent governs this revision. Required: a revision
+	// with no governing intent cannot be audited.
+	Intent    RevisionIntent   `json:"intent" yaml:"intent"`
+	Interface InterfaceID      `json:"interface" yaml:"interface"`
+	Policy    RevisionPolicy   `json:"policy" yaml:"policy"`
+	Routing   *RevisionRouting `json:"routing,omitempty" yaml:"routing,omitempty"`
+
+	// Out-of-process attachment: the adapter is an upstream reached over the network,
+	// so it may be implemented in any language.
+	Runtime       RevisionRuntime `json:"runtime" yaml:"runtime"`
+	SchemaVersion SchemaVersion   `json:"schema_version" yaml:"schema_version"`
+
+	// The router accepts only signed published descriptors (ArchitectureBlueprint.md
+	// section 35). The signature covers the canonical form of this document with the
+	// signature member removed.
+	Signature *RevisionSignature `json:"signature,omitempty" yaml:"signature,omitempty"`
+
+	// The router refuses to route to created, failed or retired revisions
+	// (ArchitectureBlueprint.md section 5.3).
+	State RevisionState `json:"state" yaml:"state"`
+}
+
+// The runtime-facing projection of a revision, deliberately small enough to be
+// consumed deterministically by infrastructure (ArchitectureBlueprint.md section
+// 36). This is a wire artifact: the gateway must be able to read it without any
+// fluid-core library.
+type RevisionDescriptorDocument struct {
+	Revision Revision `json:"revision" yaml:"revision"`
+}