refactor(migration): split model and category helpers (#1561)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/shared/migration/model-versions.ts

@@ -0,0 +1,49 @@
+/**
+ * Model version migration map: old full model strings → new full model strings.
+ * Used to auto-upgrade hardcoded model versions in user configs when the plugin
+ * bumps to newer model versions.
+ *
+ * Keys are full "provider/model" strings. Only openai and anthropic entries needed.
+ */
+export const MODEL_VERSION_MAP: Record<string, string> = {
+  "openai/gpt-5.2-codex": "openai/gpt-5.3-codex",
+  "anthropic/claude-opus-4-5": "anthropic/claude-opus-4-6",
+}
+
+function migrationKey(oldModel: string, newModel: string): string {
+  return `model-version:${oldModel}->${newModel}`
+}
+
+export function migrateModelVersions(
+  configs: Record<string, unknown>,
+  appliedMigrations?: Set<string>
+): { migrated: Record<string, unknown>; changed: boolean; newMigrations: string[] } {
+  const migrated: Record<string, unknown> = {}
+  let changed = false
+  const newMigrations: string[] = []
+
+  for (const [key, value] of Object.entries(configs)) {
+    if (value && typeof value === "object" && !Array.isArray(value)) {
+      const config = value as Record<string, unknown>
+      if (typeof config.model === "string" && MODEL_VERSION_MAP[config.model]) {
+        const oldModel = config.model
+        const newModel = MODEL_VERSION_MAP[oldModel]
+        const mKey = migrationKey(oldModel, newModel)
+
+        // Skip if this migration was already applied (user may have reverted)
+        if (appliedMigrations?.has(mKey)) {
+          migrated[key] = value
+          continue
+        }
+
+        migrated[key] = { ...config, model: newModel }
+        changed = true
+        newMigrations.push(mKey)
+        continue
+      }
+    }
+    migrated[key] = value
+  }
+
+  return { migrated, changed, newMigrations }
+}