refactor: replace extractRefs with schema casRef annotations

Migrate all templates to use .meta({ casRef: true }) on Zod schema
fields instead of manual extractRefs functions. Remove extractRefs
from RoleDefinition type entirely.

- develop: planner phases[].hash, coder completedPhase annotated
- solve-issue, smoke, init templates: extractRefs removed
- create-workflow.ts: uses collectCasRefs(schema, meta)
- RoleDefinition: extractRefs field removed (breaking)

218 tests pass, 0 fail.

Fixes #289, Refs #285

packages/workflow-protocol/src/types.ts

@@ -179,7 +179,6 @@ export type RoleDefinition<Meta extends Record<string, unknown>> = {
   description: string;
   systemPrompt: string;
   schema: z.ZodType<Meta>;
-  extractRefs: ((meta: Meta) => string[]) | null;
 };
 
 export type Moderator<M extends RoleMeta> = (