refactor(reader): rewrite reader module for foliate-js pan/zoom integration

Major rewrite of the web reader to properly interface with
@bookhoard/foliate-js, replacing the abandoned panel-detection
architecture with direct pan and zoom support built into the
foliate-js FixedLayout renderer.

Template (reader.templ):
- Fix critical bug: x-init config was using literal strings
  '{ readerData.X }' inside a quoted attribute, which templ
  treated as raw text and never interpolated. Values were never
  actually passed to JavaScript. Now uses fmt.Sprintf() with
  templ's expression attribute syntax ={ }.
- Pass fileUrl from server so foliate-js can open books directly.
- Redesign bottom bar with foliate-js parity: left/right navigation
  buttons, progress slider with tick marks, and zoom controls
  (zoom out, percentage display, zoom in, magnifier, pan/select
  mode toggle for PDFs).
- Remove panel editor button and enablePanelDetection config.
- Add SVG icon styles for consistent reader controls.

Go types (templates/types.go):
- Expand ReaderMetadata with FormatGroup, MangaType,
  ReadingDirection, FileURL, and LibraryID fields needed by
  the reader frontend.

Router (internal/router/reader.go):
- Populate new ReaderMetadata fields from database values.
- Construct FileURL from library ID and file path for the
  /uploads/library-{id}/* file serving route.

Reader JS (reader.ts):
- Full rewrite modeled on foliate-js Reader class, adapted for
  Alpine.js. Opens books via view.open(fileUrl), accesses
  view.renderer for zoom/pan/navigation, and wires up keyboard
  shortcuts (+/-/0 for zoom, arrows for nav, Escape for magnifier).
- Uses view.isFixedLayout instead of importing FixedLayout class,
  avoiding a TypeScript module resolution issue with the Vite alias.

Settings manager (settings-manager.ts):
- Remove dependency on deleted ReaderContext event bus.
- Export loadSettings/saveSettings/syncSettings directly as
  standalone async functions.

Cleanup:
- Delete reader-context.ts and reader-events.ts (over-engineered
  event system replaced by direct function calls).
- Remove panel_zoom_enabled from ReaderSettings type.

templates/types.go

@@ -147,15 +147,20 @@ func (u UnsafeHTML) ToComponent() templ.Component {
 
 // Reader types
 type ReaderMetadata struct {
-	MediaItemID    string `json:"media_item_id"`
-	Title          string `json:"title"`
-	Author         string `json:"author"`
-	CoverImagePath string `json:"cover_image_path"`
-	LibraryType    string `json:"library_type"`
-	MimeType       string `json:"mime_type"`
-	FilePath       string `json:"file_path"`
-	TotalPages     int    `json:"total_pages"`
-	ChapterCount   int    `json:"chapter_count"`
+	MediaItemID      string `json:"media_item_id"`
+	Title            string `json:"title"`
+	Author           string `json:"author"`
+	CoverImagePath   string `json:"cover_image_path"`
+	LibraryType      string `json:"library_type"`
+	MimeType         string `json:"mime_type"`
+	FilePath         string `json:"file_path"`
+	TotalPages       int    `json:"total_pages"`
+	ChapterCount     int    `json:"chapter_count"`
+	FormatGroup      string `json:"format_group"`
+	MangaType        string `json:"manga_type"`
+	ReadingDirection string `json:"reading_direction"`
+	FileURL          string `json:"file_url"`
+	LibraryID        string `json:"library_id"`
 }
 
 type ReadingProgress struct {