feat(examples): rewrite baker-family as coherent Competition Week narrative

Rewrote the baker-family example around a unified story: the annual Harvest
Baking Competition is Saturday. Martha's sourdough starter Old Maggie is
sluggish from a cold snap, Jane is secretly entering the FreeStyle category,
Emma's science fair project is "The Chemistry of Fermentation", Henry is
judging for the first time and worried about impartiality, and Roland is
defending last year's title.

The week's schedules (Mon guild meeting → Tue test bakes → Wed sourcing →
Thu dough prep → Fri science fair → Sat competition → Sun recovery) are
now fully populated with narrative-specific actions.

Files split for composability:
- behaviors/baker_behaviors.sb → 5 focused files by character/domain
- schema/types.sb → 4 files (core, baking, world, social)
- schedules/work_schedules.sb → 4 files (one per schedule)
- relationships/baker_family_relationships.sb → family + bakery

Strong typing: replaced all enumerable string fields with concepts
(BakerSpecialty, Occupation, LocationType, InstitutionType, ParentingStyle,
Intensity, BakeryDomain, BakingDiscipline, ManagementDomain,
CompetitiveAdvantage).

Remove new-syntax-demo.sb (superseded by baker-family example).

examples/baker-family/characters/jane.sb

@@ -12,7 +12,7 @@ character Jane from Baker {
     age: 36
 
     // Baker-specific traits
-    specialty: "pastries"
+    specialty: Pastries
     baking_skill: 0.85
     customer_relations: 0.80
     skill_tier: Journeyman
@@ -23,17 +23,28 @@ character Jane from Baker {
 
     // Work ethic
     work_ethic: 0.90
-    occupation: "pastry chef"
+    occupation: PastryChef
 
     ---backstory
     Jane trained at a culinary school in the capital before returning
-    to her hometown and meeting Martha. Her specialty is delicate
-    pastries and elaborate wedding cakes. While Martha handles the
-    bread and business, Jane focuses on the artistic creations that
-    draw customers from neighboring towns.
+    to her hometown and meeting Martha. Her croissants are legendary —
+    people drive from three towns over for the Saturday batch. While
+    Martha handles bread and business, Jane creates the artistic
+    pastries that fill the display cases.
 
-    She is more of a night owl by nature, but has adapted to the baker's
-    early schedule over the years. Her croissants are legendary.
+    This year, for the first time, Jane is entering the Harvest Baking
+    Competition herself, in the FreeStyle category. She has been
+    secretly practicing an ambitious croquembouche after Emma's
+    bedtime: a tower of cream puffs held together with spun caramel,
+    decorated with candied violets from their garden. Martha does not
+    know the full scope of what Jane is planning — Jane wants to
+    surprise her.
+
+    She is nervous. She has always been the support crew on competition
+    day, packing Martha's tools and keeping the workspace organized.
+    Stepping out from behind the scenes feels like a risk, but Emma
+    keeps telling her she should, and Martha has been encouraging her
+    for years.
     ---
 }