feat: add series support for book organization

API:
- Add /libraries/{id}/series endpoint to list series with book counts
- Add series filter to /books endpoint
- Fix SeriesItem to return first_book_id properly (using CTE with ROW_NUMBER)

Indexer:
- Parse series from parent folder name relative to library root
- Store series in database when indexing books

Backoffice:
- Add Books page with grid view, search, and pagination
- Add Series page showing series with cover images
- Add Library books page filtered by series
- Add book detail page
- Add Series column in libraries list with clickable link
- Create BookCard component for reusable book display
- Add CSS styles for books grid, series grid, and book details
- Add proxy API route for book cover images (fixing CORS issues)

Parser:
- Add series field to ParsedMetadata
- Extract series from file path relative to library root

Books without a parent folder are categorized as 'unclassified' series.

crates/parsers/src/lib.rs

@@ -21,6 +21,7 @@ impl BookFormat {
 #[derive(Debug, Clone)]
 pub struct ParsedMetadata {
     pub title: String,
+    pub series: Option<String>,
     pub page_count: Option<i32>,
 }
 
@@ -34,23 +35,47 @@ pub fn detect_format(path: &Path) -> Option<BookFormat> {
     }
 }
 
-pub fn parse_metadata(path: &Path, format: BookFormat) -> Result<ParsedMetadata> {
+pub fn parse_metadata(
+    path: &Path,
+    format: BookFormat,
+    library_root: &Path,
+) -> Result<ParsedMetadata> {
     let title = path
         .file_stem()
         .map(|s| s.to_string_lossy().to_string())
         .unwrap_or_else(|| "Untitled".to_string());
 
+    // Determine series from parent folder relative to library root
+    let series = path.parent().and_then(|parent| {
+        // Get the relative path from library root to parent
+        let relative = parent.strip_prefix(library_root).ok()?;
+        // If relative path is not empty, use first component as series
+        let first_component = relative.components().next()?;
+        let series_name = first_component.as_os_str().to_string_lossy().to_string();
+        // Only if series_name is not empty
+        if series_name.is_empty() {
+            None
+        } else {
+            Some(series_name)
+        }
+    });
+
     let page_count = match format {
         BookFormat::Cbz => parse_cbz_page_count(path).ok(),
         BookFormat::Cbr => parse_cbr_page_count(path).ok(),
         BookFormat::Pdf => parse_pdf_page_count(path).ok(),
     };
 
-    Ok(ParsedMetadata { title, page_count })
+    Ok(ParsedMetadata {
+        title,
+        series,
+        page_count,
+    })
 }
 
 fn parse_cbz_page_count(path: &Path) -> Result<i32> {
-    let file = std::fs::File::open(path).with_context(|| format!("cannot open cbz: {}", path.display()))?;
+    let file = std::fs::File::open(path)
+        .with_context(|| format!("cannot open cbz: {}", path.display()))?;
     let mut archive = zip::ZipArchive::new(file).context("invalid cbz archive")?;
     let mut count: i32 = 0;
     for i in 0..archive.len() {
@@ -83,7 +108,8 @@ fn parse_cbr_page_count(path: &Path) -> Result<i32> {
 }
 
 fn parse_pdf_page_count(path: &Path) -> Result<i32> {
-    let doc = lopdf::Document::load(path).with_context(|| format!("cannot open pdf: {}", path.display()))?;
+    let doc = lopdf::Document::load(path)
+        .with_context(|| format!("cannot open pdf: {}", path.display()))?;
     Ok(doc.get_pages().len() as i32)
 }