feat: implement storybook DSL with template composition and validation

Add complete domain-specific language for authoring narrative content for
agent simulations.

Features:
- Complete parser using LALRPOP + logos lexer
- Template composition (includes + multiple inheritance)
- Strict mode validation for templates
- Reserved keyword protection
- Semantic validators (trait ranges, schedule overlaps, life arcs, behaviors)
- Name resolution and cross-reference tracking
- CLI tool (validate, inspect, query commands)
- Query API with filtering
- 260 comprehensive tests (unit, integration, property-based)

Implementation phases:
- Phase 1 (Parser): Complete
- Phase 2 (Resolution + Validation): Complete
- Phase 3 (Public API + CLI): Complete

BREAKING CHANGE: Initial implementation

tests/examples/relationship_merging.sb

@@ -0,0 +1,74 @@
+// Demonstration of relationship merging
+// The same relationship can be declared multiple times from different perspectives
+// The resolver will merge them into a single relationship
+
+// First, define characters
+character Alice {
+    age: 30
+    name: "Alice"
+}
+
+character Bob {
+    age: 32
+    name: "Bob"
+}
+
+// Declare the relationship from Alice's perspective
+// In a multi-file system, this might be in alice.sb
+relationship Friendship_AliceBob {
+    Alice self {
+        // Alice's feelings about the friendship
+        trust: 0.9
+        enjoyment: 0.95
+    } other {
+        // How Alice perceives Bob
+        reliability: 0.85
+        humor: 0.9
+    }
+    Bob
+}
+
+// Same relationship from Bob's perspective
+// In a multi-file system, this might be in bob.sb
+relationship Friendship_AliceBob {
+    Bob self {
+        // Bob's feelings about the friendship
+        trust: 0.85
+        enjoyment: 0.9
+    } other {
+        // How Bob perceives Alice
+        reliability: 0.95
+        humor: 0.8
+    }
+    Alice
+}
+
+// The resolver will:
+// 1. Recognize these as the same relationship (same participants + name)
+// 2. Merge the self/other blocks appropriately
+// 3. Validate that shared fields (if any) have the same values
+
+// Example with shared fields
+relationship Professional_AliceBob {
+    Alice self {
+        respect: 0.9
+    }
+    Bob
+    
+    // Shared field - must have same value in all declarations
+    workplace: "TechCorp"
+}
+
+// Same relationship, same shared field value
+relationship Professional_AliceBob {
+    Bob self {
+        respect: 0.85
+    }
+    Alice
+    
+    // This MUST match the value in the other declaration
+    workplace: "TechCorp"
+}
+
+// Note: If the shared field values differed, the resolver would
+// report a validation error about conflicting values