refactor: migrate to clean architecture with trait-based DI (v0.2.0)

Complete architectural overhaul across all 12 crates:

- Replace validator crate with zod-rs for all DTO validation
- Replace manual pagination with paginator-rs/paginator-sea-orm
- Migrate all modules (iam, cms, gacha, dimentorin) to clean architecture:
  domain → application → infrastructure layers
- Introduce trait-based DI (Arc<dyn Trait>) at every layer for repositories and services
- Delete all v1/ legacy SurrealDB-era code across every crate
- Replace opaque response helpers with typed IntoResponse structs (ApiSuccess, ApiCreated, ApiPaginated, ApiMessage)
- Remove dual_mode_repository, migration_validation_errors, validator.rs dead code
- Zero cargo clippy warnings; release build clean

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

imphnen-dimentorin/src/sessions/domain/repository.rs

@@ -0,0 +1,48 @@
+use async_trait::async_trait;
+use paginator_rs::PaginationParams;
+use paginator_utils::PaginatorResponse;
+use uuid::Uuid;
+use imphnen_utils::AppError;
+use super::session::SessionEntity;
+
+#[async_trait]
+pub trait SessionRepository: Send + Sync {
+    async fn create(&self, entity: SessionEntity) -> Result<SessionEntity, AppError>;
+
+    async fn find_by_id(&self, id: Uuid) -> Result<Option<SessionEntity>, AppError>;
+
+    async fn find_by_mentor_id(
+        &self,
+        mentor_id: Uuid,
+        status_filter: Option<String>,
+    ) -> Result<Vec<SessionEntity>, AppError>;
+
+    async fn find_by_mentee_id(
+        &self,
+        mentee_id: Uuid,
+        status_filter: Option<String>,
+    ) -> Result<Vec<SessionEntity>, AppError>;
+
+    async fn find_booked_dates(&self, mentor_id: Uuid) -> Result<Vec<String>, AppError>;
+
+    async fn update(&self, id: Uuid, entity: SessionEntity) -> Result<SessionEntity, AppError>;
+
+    async fn delete(&self, id: Uuid) -> Result<(), AppError>;
+
+    async fn count_by_mentor(
+        &self,
+        mentor_id: Uuid,
+        status_filter: Option<String>,
+    ) -> Result<usize, AppError>;
+
+    async fn count_by_mentee(
+        &self,
+        mentee_id: Uuid,
+        status_filter: Option<String>,
+    ) -> Result<usize, AppError>;
+
+    async fn find_all_paginated(
+        &self,
+        params: PaginationParams,
+    ) -> Result<PaginatorResponse<SessionEntity>, AppError>;
+}