feat: consolidate schema changes from crew directories

Merges schema additions from crew/fang, crew/giles, crew/grip, and crew/wolf:

- crystallizes: bool field for work economics (compounds vs evaporates)
- work_type: WorkType field for assignment model (mutex vs open_competition)
- source_system: string field for federation adapter tracking
- quality_score: *float32 for aggregate quality (0.0-1.0)
- delegated-from: new dependency type for work delegation chains

Migrations properly sequenced as 037-040 (after existing 036 owner_column).

Also fixes test compilation errors for removed TypeRig and IsBuiltIn references.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Executed-By: beads/crew/dave
Rig: beads
Role: crew

internal/storage/sqlite/migrations/039_source_system_column.go

@@ -0,0 +1,33 @@
+package migrations
+
+import (
+	"database/sql"
+	"fmt"
+)
+
+// MigrateSourceSystemColumn adds the source_system column to the issues table.
+// This tracks which adapter/system created the issue for federation support.
+func MigrateSourceSystemColumn(db *sql.DB) error {
+	// Check if column already exists
+	var columnExists bool
+	err := db.QueryRow(`
+		SELECT COUNT(*) > 0
+		FROM pragma_table_info('issues')
+		WHERE name = 'source_system'
+	`).Scan(&columnExists)
+	if err != nil {
+		return fmt.Errorf("failed to check source_system column: %w", err)
+	}
+
+	if columnExists {
+		return nil
+	}
+
+	// Add the source_system column
+	_, err = db.Exec(`ALTER TABLE issues ADD COLUMN source_system TEXT DEFAULT ''`)
+	if err != nil {
+		return fmt.Errorf("failed to add source_system column: %w", err)
+	}
+
+	return nil
+}