fix(core,fuse,gui): date photos by their EXIF when nothing else does

A Takeout photo with no sidecar and no date in its name was filed under
the day of the import, and the app dated uploads by modification time.
A new `exiftime` module reads DateTimeOriginal (then DateTimeDigitized)
with its offset. Takeout uses it for undated photos it copies out for a
thumbnail, and the daemon uses it for app uploads before falling back to
the modification time (B244).

crates/pdfs-fuse/src/control.rs

@@ -911,6 +911,17 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 ))),
                 Ok((file, len)) => {
                     let photos = core.photos();
+                    // Unless the caller knows better: the photo's own EXIF,
+                    // then the file's modification time, which a copy resets.
+                    let capture_time = capture_time.or_else(|| {
+                        let path = Path::new(&source_path);
+                        pdfs_core::exiftime::capture_time_of(path).or_else(|| {
+                            let modified =
+                                std::fs::metadata(path).and_then(|m| m.modified()).ok()?;
+                            let since = modified.duration_since(std::time::UNIX_EPOCH).ok()?;
+                            Some(since.as_secs() as i64)
+                        })
+                    });
                     let metadata = proton_drive_rs::PhotoUploadMetadata {
                         capture_time,
                         ..Default::default()

crates/pdfs-fuse/src/takeout.rs

@@ -363,6 +363,14 @@ impl Core {
                 let uploaded = match &staged {
                     Some(path) => {
                         let thumbnails = self.upload_thumbnails(path, &photo.name);
+                        // No sidecar and no date in the name: the photo's own
+                        // EXIF, before Drive files it under today.
+                        let metadata = PhotoUploadMetadata {
+                            capture_time: metadata
+                                .capture_time
+                                .or_else(|| pdfs_core::exiftime::capture_time_of(path)),
+                            ..metadata
+                        };
                         std::fs::File::open(path)
                             .map_err(|e| {
                                 CoreError::internal(format!("open {}: {e}", path.display()))