perf: round 23 — Postgres query-shape pass: typed JSONB decode, drive-policy borrow-deserialize, user-profile join!, subject-group CTE reuse, dedup unzip

Benchmark-gated, same rule as ROUND2-22: BEFORE/AFTER with a value-equivalence
gate and rollback-on-regression. Two harnesses — bench_round23_micro (no
Postgres; deterministic allocation gate) and bench_round23_queries (live
Postgres; p50 latency + strict equivalence gate against seeded fixtures). See
benches/ROUND23.md.

- J1: contact_pg_repository::row_to_contact (+ the inlined contact_group sibling)
  decode the 3 JSONB columns via sqlx::types::Json<T> (one from_slice pass)
  instead of row.get::<serde_json::Value> + from_value (a throwaway Value DOM
  per column, walked a second time). Per contact row of every list / multiget /
  CardDAV sync. Micro 84 -> 33 allocs/op (2.15x); PG 3794 -> 2360 ns/contact
  (1.61x) on 500 real rows.
- J2: DrivePolicies::from_value deserializes straight from the borrow
  (T::deserialize(&Value)) instead of from_value(value.clone()) — dropping the
  full-DOM clone on every drive-policy read (move/copy, share, grant); one-line
  body change, all 7 callers unchanged. Micro 5 -> 0 allocs/op (11.51x).
- P1: get_user_profile overlaps the two independent caller+target reads with
  tokio::join! (self-case still a single fetch; caller-error precedence
  preserved via caller_res? first) instead of two serial round-trips. PG
  577 -> 312 us/call (1.85x).
- G1: subject_group remove_member computes the child's transitive-user recursive
  CTE once and reuses it for both the would-empty pre-check and the cache
  invalidation, instead of running the identical CTE twice (the edge delete is
  above the child, so its descendants can't change). PG 829 -> 412 us/removal
  (2.01x).
- U1: dedup_service (store_loose_chunks final registration + the ingest
  run_rollback) reshapes the owned, dead-after Vec<(String,i64)> via
  into_iter().unzip() instead of cloning every 64-byte hash for the
  sync_blobs(&[String]) + UNNEST bind. Micro 256 -> 0 hash clones.

Verified: cargo clippy --features bench --all-targets -D warnings clean, cargo
fmt --all --check clean, cargo test --lib --features bench = 529 passed / 0
failed. The PG benches run against a local PostgreSQL 16 (schema applied from
migrations/); every equivalence gate passes.

The download_zip per-item N+1 (the audit's highest raw-latency candidate) is
deferred to a dedicated pass: its fix moves the sole authorization inside the
stream call, so it needs an AuthZ-ordering + anti-enumeration proof, not a perf
banner.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DKyQ4AnYtgp1JtjzweyMeo

src/infrastructure/repositories/pg/contact_group_pg_repository.rs

@@ -1,5 +1,4 @@
 use chrono::Utc;
-use serde_json::Value as JsonValue;
 use sqlx::{PgPool, Row, types::Uuid};
 use std::sync::Arc;
 
@@ -220,18 +219,21 @@ impl ContactGroupRepository for ContactGroupPgRepository {
 
         let mut contacts = Vec::with_capacity(rows.len());
         for row in &rows {
-            let email_json: JsonValue = row.get("email");
-            let phone_json: JsonValue = row.get("phone");
-            let address_json: JsonValue = row.get("address");
-
-            let emails = serde_json::from_value::<Vec<EmailPersistenceDto>>(email_json)
-                .map(emails_from_persistence)
+            // Typed `Json<T>` decode (one `from_slice` pass) instead of the
+            // `Value` DOM + `from_value` re-walk — the contact_pg_repository
+            // §J1 fix applied to this inlined sibling. Byte-identical result,
+            // 3 fewer throwaway DOMs per contact. (benches/ROUND23.md §J1)
+            let emails = row
+                .try_get::<sqlx::types::Json<Vec<EmailPersistenceDto>>, _>("email")
+                .map(|j| emails_from_persistence(j.0))
                 .unwrap_or_default();
-            let phones = serde_json::from_value::<Vec<PhonePersistenceDto>>(phone_json)
-                .map(phones_from_persistence)
+            let phones = row
+                .try_get::<sqlx::types::Json<Vec<PhonePersistenceDto>>, _>("phone")
+                .map(|j| phones_from_persistence(j.0))
                 .unwrap_or_default();
-            let addresses = serde_json::from_value::<Vec<AddressPersistenceDto>>(address_json)
-                .map(addresses_from_persistence)
+            let addresses = row
+                .try_get::<sqlx::types::Json<Vec<AddressPersistenceDto>>, _>("address")
+                .map(|j| addresses_from_persistence(j.0))
                 .unwrap_or_default();
 
             contacts.push(Contact::from_raw(

src/infrastructure/repositories/pg/contact_pg_repository.rs

@@ -23,18 +23,27 @@ impl ContactPgRepository {
 
     /// Maps a database row to a Contact domain entity
     fn row_to_contact(row: &sqlx::postgres::PgRow) -> Result<Contact, DomainError> {
-        let email_json: JsonValue = row.get("email");
-        let phone_json: JsonValue = row.get("phone");
-        let address_json: JsonValue = row.get("address");
-
-        let emails = serde_json::from_value::<Vec<EmailPersistenceDto>>(email_json)
-            .map(emails_from_persistence)
+        // Decode each JSONB column straight into its typed Vec via
+        // `sqlx::types::Json<T>` (a single `serde_json::from_slice` pass over
+        // the raw JSONB bytes) instead of `row.get::<serde_json::Value>` +
+        // `serde_json::from_value`, which built a throwaway `Value` DOM per
+        // column and then walked it a SECOND time to produce the typed Vec —
+        // 3 discarded DOMs per contact row on every list / multiget / CardDAV
+        // sync. `try_get` preserves the exact malformed-shape fallback (the old
+        // `from_value(...).unwrap_or_default()`; a bare `row.get` would panic on
+        // a decode error); the columns are `JSONB NOT NULL DEFAULT '[]'`, so SQL
+        // NULL never occurs. (benches/ROUND23.md §J1)
+        let emails = row
+            .try_get::<sqlx::types::Json<Vec<EmailPersistenceDto>>, _>("email")
+            .map(|j| emails_from_persistence(j.0))
             .unwrap_or_default();
-        let phones = serde_json::from_value::<Vec<PhonePersistenceDto>>(phone_json)
-            .map(phones_from_persistence)
+        let phones = row
+            .try_get::<sqlx::types::Json<Vec<PhonePersistenceDto>>, _>("phone")
+            .map(|j| phones_from_persistence(j.0))
             .unwrap_or_default();
-        let addresses = serde_json::from_value::<Vec<AddressPersistenceDto>>(address_json)
-            .map(addresses_from_persistence)
+        let addresses = row
+            .try_get::<sqlx::types::Json<Vec<AddressPersistenceDto>>, _>("address")
+            .map(|j| addresses_from_persistence(j.0))
             .unwrap_or_default();
 
         Ok(Contact::from_raw(