fix(dates): prefer earliest of fs created/modified as fallback

On copied or restored files (e.g. a backup library), the OS stamps
created at copy time while modified is preserved from the source, so
the earlier of the two is a better proxy for when the content
originated. Adds utils::earliest_fs_time and threads it through the
three spots that fall back to filesystem dates: photos-list sort,
memories grouping, and insight-generation timestamp.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ai/insight_generator.rs

@@ -23,7 +23,7 @@ use crate::libraries::Library;
 use crate::memories::extract_date_from_filename;
 use crate::otel::global_tracer;
 use crate::tags::TagDao;
-use crate::utils::normalize_path;
+use crate::utils::{earliest_fs_time, normalize_path};
 
 #[derive(Deserialize)]
 struct NominatimResponse {
@@ -760,8 +760,6 @@ impl InsightGenerator {
                     let full_path = self.resolve_full_path(&file_path)?;
                     File::open(&full_path)
                         .and_then(|f| f.metadata())
-                        .and_then(|m| m.created().or(m.modified()))
-                        .map(|t| DateTime::<Utc>::from(t).timestamp())
                         .inspect_err(|e| {
                             log::warn!(
                                 "Failed to get file timestamp for insight {}: {}",
@@ -770,6 +768,8 @@ impl InsightGenerator {
                             )
                         })
                         .ok()
+                        .and_then(|m| earliest_fs_time(&m))
+                        .map(|t| DateTime::<Utc>::from(t).timestamp())
                 })
                 .unwrap_or_else(|| Utc::now().timestamp())
         };
@@ -1687,7 +1687,11 @@ Return ONLY the summary, nothing else."#,
                     let date = chrono::DateTime::from_timestamp(h.date, 0)
                         .map(|dt| dt.format("%Y-%m-%d").to_string())
                         .unwrap_or_else(|| h.date.to_string());
-                    let direction: &str = if h.type_ == 2 { &user_name } else { &h.contact_name };
+                    let direction: &str = if h.type_ == 2 {
+                        &user_name
+                    } else {
+                        &h.contact_name
+                    };
                     let score = h
                         .similarity_score
                         .map(|s| format!(" [score {:.2}]", s))
@@ -2858,8 +2862,6 @@ Return ONLY the summary, nothing else."#,
                     let full_path = self.resolve_full_path(&file_path)?;
                     File::open(&full_path)
                         .and_then(|f| f.metadata())
-                        .and_then(|m| m.created().or(m.modified()))
-                        .map(|t| DateTime::<Utc>::from(t).timestamp())
                         .inspect_err(|e| {
                             log::warn!(
                                 "Failed to get file timestamp for agentic insight {}: {}",
@@ -2868,6 +2870,8 @@ Return ONLY the summary, nothing else."#,
                             )
                         })
                         .ok()
+                        .and_then(|m| earliest_fs_time(&m))
+                        .map(|t| DateTime::<Utc>::from(t).timestamp())
                 })
                 .unwrap_or_else(|| Utc::now().timestamp())
         };

src/files.rs

@@ -15,6 +15,7 @@ use crate::database::ExifDao;
 use crate::file_types;
 use crate::geo::{gps_bounding_box, haversine_distance};
 use crate::memories::extract_date_from_filename;
+use crate::utils::earliest_fs_time;
 use crate::{AppState, create_thumbnails};
 use actix_web::web::Data;
 use actix_web::{
@@ -138,8 +139,8 @@ fn in_memory_date_sort(
                     lib_roots.get(&lib_id).and_then(|root| {
                         let full_path = Path::new(root).join(&f.file_name);
                         std::fs::metadata(full_path)
-                            .and_then(|md| md.created().or(md.modified()))
                             .ok()
+                            .and_then(|md| earliest_fs_time(&md))
                             .map(|system_time| {
                                 <SystemTime as Into<DateTime<Utc>>>::into(system_time).timestamp()
                             })

src/memories.rs

@@ -19,6 +19,7 @@ use crate::files::is_image_or_video;
 use crate::libraries::Library;
 use crate::otel::{extract_context_from_request, global_tracer};
 use crate::state::AppState;
+use crate::utils::earliest_fs_time;
 
 // Helper that encapsulates path-exclusion semantics
 #[derive(Debug)]
@@ -336,8 +337,8 @@ fn get_memory_date_with_priority(
         return Some((date, Some(exif_timestamp), modified));
     }
 
-    // Priority 3: Fall back to metadata
-    let system_time = meta.created().ok().or_else(|| meta.modified().ok())?;
+    // Priority 3: Fall back to metadata (earlier of created/modified — see utils::earliest_fs_time)
+    let system_time = earliest_fs_time(&meta)?;
     let dt_utc: DateTime<Utc> = system_time.into();
 
     let date_in_timezone = if let Some(tz) = client_timezone {

src/utils.rs

@@ -1,3 +1,5 @@
+use std::time::SystemTime;
+
 /// Normalize a file path to use forward slashes for cross-platform consistency
 /// This ensures paths stored in the database always use `/` regardless of OS
 ///
@@ -12,6 +14,20 @@ pub fn normalize_path(path: &str) -> String {
     path.replace('\\', "/")
 }
 
+/// Pick the earlier of a file's created and modified timestamps.
+///
+/// On copied/restored files (e.g., a backup library), `created` is stamped at
+/// copy time while `modified` is preserved from the source — so the earlier
+/// of the two is a better proxy for when the content originated. Falls back
+/// to whichever timestamp is available if one platform lacks the other.
+pub fn earliest_fs_time(md: &std::fs::Metadata) -> Option<SystemTime> {
+    match (md.created().ok(), md.modified().ok()) {
+        (Some(c), Some(m)) => Some(c.min(m)),
+        (Some(t), None) | (None, Some(t)) => Some(t),
+        (None, None) => None,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;