refactor: extract adapter-common crate — shared sqlx error mapping,

row-to-domain conversions, date/uuid utils

Eliminates 39 map_err copies, consolidates parse_uuid/parse_datetime/
datetime_to_str/format_year_month, extracts 7 shared row-to-domain
conversion functions (movie, review, watchlist, stats, user_summary).
Row structs stay per-adapter (FromRow is db-specific), only conversion
logic is shared. Net -281 lines.

crates/adapters/postgres-federation/src/review.rs

@@ -3,7 +3,8 @@ use anyhow::{Result, anyhow};
 use async_trait::async_trait;
 use domain::models::{Review, ReviewSource};
 
-use super::{PostgresFederationRepository, datetime_to_str};
+use adapter_common::datetime_to_str;
+use super::PostgresFederationRepository;
 
 #[async_trait]
 impl RemoteReviewRepository for PostgresFederationRepository {