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/characters/emma.sb

@@ -20,16 +20,17 @@ character Emma from Child {
     mood: 0.85
 
     ---backstory
-    Emma is the bright, energetic daughter of Martha and John. She loves
+    Emma is the bright, energetic daughter of Martha and Jane. She loves
     helping in the bakery on weekends, though she's not allowed to work
     the ovens yet. She's fascinated by the chemistry of baking and often
-    asks her parents endless questions about why dough rises, how yeast
+    asks her mothers endless questions about why dough rises, how yeast
     works, and what makes bread crusty.
 
     At school, she excels in science and math, and dreams of one day
-    creating her own innovative recipes. For now, she's content to help
-    package goods and chat with the regular customers who've watched her
-    grow up.
+    creating her own innovative recipes. She learns the science of bread
+    from Martha and the art of decoration from Jane. For now, she's
+    content to help package goods and chat with the regular customers
+    who've watched her grow up.
     ---
 }