PR-001: Domain Model v1.0 — compile-only, zero dependencies

- @landvex/domain package with TypeScript strict mode
- 3 Aggregate Roots: FieldSession, Mission, DecisionCase
- Branded IDs, Value Objects, Domain Events, Invariants
- 19 unit tests for IDs, FieldSession, DecisionCase
- Zero runtime dependencies (only TypeScript + jest for tests)
- Separates Entity / Value Object / Aggregate Root
- README documents Three Rules of the domain

Definition of Done met:
- Compiles without errors
- Exports all domain types
- Unit tests for invariants and value objects
- No PostgreSQL, S3, Express, AI models, queues

packages/domain/src/common/ids.ts

@@ -0,0 +1,63 @@
+/**
+ * Branded ID types for type safety
+ * Prevents mixing different ID types accidentally
+ */
+
+export type SessionId = string & { readonly __brand: 'SessionId' };
+export type MissionId = string & { readonly __brand: 'MissionId' };
+export type ArtifactId = string & { readonly __brand: 'ArtifactId' };
+export type ObservationId = string & { readonly __brand: 'ObservationId' };
+export type DecisionId = string & { readonly __brand: 'DecisionId' };
+export type EvidenceId = string & { readonly __brand: 'EvidenceId' };
+export type FindingId = string & { readonly __brand: 'FindingId' };
+export type ReviewId = string & { readonly __brand: 'ReviewId' };
+export type ActionId = string & { readonly __brand: 'ActionId' };
+export type OutcomeId = string & { readonly __brand: 'OutcomeId' };
+
+/**
+ * ID factory functions
+ * Ensures consistent ID format across the domain
+ */
+export const IdFactory = {
+  session: (date: Date, sequence: number): SessionId => {
+    const dateStr = date.toISOString().split('T')[0].replace(/-/g, '');
+    return `session_${dateStr}_${sequence.toString().padStart(6, '0')}` as SessionId;
+  },
+
+  mission: (date: Date, sequence: number): MissionId => {
+    const dateStr = date.toISOString().split('T')[0].replace(/-/g, '');
+    return `mission_${dateStr}_${sequence.toString().padStart(6, '0')}` as MissionId;
+  },
+
+  artifact: (sequence: number): ArtifactId => {
+    return `artifact_${sequence.toString().padStart(6, '0')}` as ArtifactId;
+  },
+
+  observation: (sequence: number): ObservationId => {
+    return `obs_${sequence.toString().padStart(6, '0')}` as ObservationId;
+  },
+
+  decision: (sequence: number): DecisionId => {
+    return `decision_${sequence.toString().padStart(6, '0')}` as DecisionId;
+  },
+
+  evidence: (sequence: number): EvidenceId => {
+    return `evidence_${sequence.toString().padStart(6, '0')}` as EvidenceId;
+  },
+
+  finding: (sequence: number): FindingId => {
+    return `finding_${sequence.toString().padStart(6, '0')}` as FindingId;
+  },
+
+  review: (sequence: number): ReviewId => {
+    return `review_${sequence.toString().padStart(6, '0')}` as ReviewId;
+  },
+
+  action: (sequence: number): ActionId => {
+    return `action_${sequence.toString().padStart(6, '0')}` as ActionId;
+  },
+
+  outcome: (sequence: number): OutcomeId => {
+    return `outcome_${sequence.toString().padStart(6, '0')}` as OutcomeId;
+  }
+};