perf: migrate all user/session/auth IDs from VARCHAR(36) to native UUID

- Schema: all ~15 VARCHAR(36) columns → UUID with DEFAULT gen_random_uuid()
- Domain entities: User, Session, DeviceCode, AppPassword, Share → id: Uuid
- DTOs: CurrentUser.id → Uuid (API boundary DTOs keep String for JSON)
- Auth middleware: parse JWT claims.sub (String) → Uuid at boundary
- All repository traits, port traits, service impls updated end-to-end
- Handlers: pass Uuid by value (Copy, 16 bytes) instead of String refs
- Settings chain: updated_by column → Uuid (was text, caused setup crash)
- Removed ~650 lines of String↔Uuid conversion boilerplate
- Eliminates per-request heap allocations for ID cloning
- 16-byte binary comparison vs 36-byte string comparison in all queries
- Native UUID indexing in PostgreSQL (btree on 16 bytes vs 36-char text)

85 files changed, 1090 insertions(+), 1739 deletions(-)

Dockerfile

@@ -1,5 +1,5 @@
 # Stage 1: Cache dependencies
-FROM rust:1.93.0-alpine3.23 AS cacher
+FROM rust:1.94.0-alpine3.23 AS cacher
 WORKDIR /app
 RUN apk --no-cache upgrade && \
     apk add --no-cache musl-dev pkgconfig postgresql-dev gcc perl make
@@ -10,7 +10,7 @@ RUN mkdir -p src && \
     RUSTFLAGS="-C target-cpu=native" cargo build --release && \
     rm -rf src target/release/deps/oxicloud*
 # Stage 2: Build the application
-FROM rust:1.93.0-alpine3.23 AS builder
+FROM rust:1.94.0-alpine3.23 AS builder
 WORKDIR /app
 RUN apk --no-cache upgrade && \
     apk add --no-cache musl-dev pkgconfig postgresql-dev gcc perl make