feat(examples): expand baker-family with relationships and world context

Added comprehensive v0.3.0 feature demonstration:

Characters (5 total):
- Martha & Jane (married lesbian couple, co-owners of bakery)
- Emma (their daughter, apprentice baker)
- Henry (loyal customer, retired teacher)
- Roland (competing baker)

New declarations:
- 6 relationships with asymmetric perspectives (Marriage, ParentChild×2,
  BusinessPartnership, CustomerRelationship, Competition)
- Locations with prose (MarthasBakery, MainStreet)
- Institution (BakersGuild)
- Life arcs (MarriageQuality, BusinessGrowth)

Features demonstrated:
- Concept comparison usage (skill_tier: Master/Journeyman)
- Life arc applied to relationship
- Asymmetric participant perspectives
- Family coherence across files

examples/baker-family/relationships/baker_family_relationships.sb

@@ -0,0 +1,96 @@
+//! Relationships for the Baker family
+//!
+//! Demonstrates:
+//! - Multiple relationship types
+//! - Asymmetric participant perspectives (roles)
+//! - Participant-specific fields
+//! - Shared relationship fields
+
+// Marriage between Martha and Jane
+relationship Marriage {
+    Martha as wife {
+        commitment: 0.95
+        role_in_bakery: "business and bread"
+    }
+
+    Jane as wife {
+        commitment: 0.95
+        role_in_bakery: "pastries and cakes"
+    }
+
+    years_together: 14
+    relationship_quality: 0.90
+}
+
+// Martha and Emma - parent/child
+relationship ParentChild_MarthaEmma {
+    Martha as parent {
+        parenting_style: "encouraging"
+        teaches: "baking fundamentals"
+    }
+
+    Emma as child {
+        admiration: 0.9
+        learns_from: "baking science"
+    }
+}
+
+// Jane and Emma - parent/child
+relationship ParentChild_JaneEmma {
+    Jane as parent {
+        parenting_style: "creative"
+        teaches: "pastry decoration"
+    }
+
+    Emma as child {
+        admiration: 0.85
+        learns_from: "artistic expression"
+    }
+}
+
+// Martha and Jane - business partnership (they co-run the bakery)
+relationship BusinessPartnership {
+    Martha as co_owner {
+        domain: "bread and business"
+        manages: "operations and suppliers"
+    }
+
+    Jane as co_owner {
+        domain: "pastries and presentation"
+        manages: "menu design and displays"
+    }
+
+    partnership_strength: 0.95
+}
+
+// Henry as loyal customer
+relationship CustomerRelationship {
+    Martha as baker {
+        service_priority: "high"
+        reserved_item: "sourdough loaf"
+    }
+
+    Henry as customer {
+        loyalty: 0.95
+        daily_visit: true
+        favorite_item: "sourdough"
+    }
+
+    years_as_customer: 8
+}
+
+// Roland and Martha - business competition
+relationship Competition {
+    Martha as competitor {
+        market_share: 0.65
+        advantage: "customer loyalty"
+    }
+
+    Roland as competitor {
+        market_share: 0.35
+        advantage: "lower prices"
+    }
+
+    intensity: 0.70
+    mutual_respect: 0.40
+}