Stored timestamps have one writer: local::iso and local::now

The store's time format (RFC 3339, UTC, milliseconds, Z) is what makes lexical
order chronological. It was spelled out ten times as
to_rfc3339_opts(SecondsFormat::Millis, true), with two private now() copies
(store, pull). local::iso(t) and local::now() now hold it; store, pull, engine
and portable call them.

DRY pass #2, batch 2, F5 (#5372).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/src/local/store.rs

@@ -7,7 +7,7 @@
 //! ("YYYY-MM-DDTHH:MM:SS.sssZ") so string ordering and date-range comparisons line
 //! up with the values the frontend sends.
 
-use chrono::{DateTime, Duration, SecondsFormat, Utc};
+use chrono::{DateTime, Duration, Utc};
 use rusqlite::{params, params_from_iter, Connection, OptionalExtension, Params};
 use serde_json::{json, Value};
 use uuid::Uuid;
@@ -15,10 +15,7 @@ use uuid::Uuid;
 use crate::local::derive;
 use crate::local::models::*;
 use crate::local::recur;
-
-fn now() -> String {
-    Utc::now().to_rfc3339_opts(SecondsFormat::Millis, true)
-}
+use crate::local::{iso, now};
 
 fn new_id() -> String {
     Uuid::new_v4().to_string()
@@ -571,8 +568,7 @@ fn should_snapshot(conn: &Connection, id: &str, new_body: &str) -> rusqlite::Res
     }
     // String comparison, not date maths: timestamps are RFC3339 UTC with a fixed
     // millisecond field (see the module header), so lexical order IS chronological.
-    let cutoff = (Utc::now() - Duration::minutes(REVISION_WINDOW_MINUTES))
-        .to_rfc3339_opts(SecondsFormat::Millis, true);
+    let cutoff = iso(Utc::now() - Duration::minutes(REVISION_WINDOW_MINUTES));
     let recent: i64 = conn.query_row(
         "SELECT COUNT(*) FROM note_revisions WHERE note_id = ?1 AND created_at >= ?2",
         params![id, cutoff],
@@ -700,7 +696,7 @@ pub fn complete_reminder(conn: &Connection, id: &str) -> rusqlite::Result<Note>
     match next {
         Some(at) => conn.execute(
             "UPDATE notes SET remind_at = ?1 WHERE id = ?2",
-            params![at.to_rfc3339_opts(SecondsFormat::Millis, true), id],
+            params![iso(at), id],
         )?,
         None => conn.execute(
             "UPDATE notes SET remind_at = NULL, recurrence = NULL WHERE id = ?1",
@@ -719,7 +715,7 @@ pub fn snooze_reminder(conn: &Connection, id: &str, minutes: i64) -> rusqlite::R
     require_owner(conn, id)?;
     // 0 or less would set a reminder in the past; a huge value overflows `Duration`.
     let minutes = minutes.clamp(1, SNOOZE_MAX_MINUTES);
-    let t = (Utc::now() + Duration::minutes(minutes)).to_rfc3339_opts(SecondsFormat::Millis, true);
+    let t = iso(Utc::now() + Duration::minutes(minutes));
     conn.execute(
         "UPDATE notes SET remind_at = ?1 WHERE id = ?2",
         params![t, id],