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.

internal/router/reader.go

@@ -6,6 +6,7 @@ import (
 	"bookhoard/internal/services"
 	"bookhoard/templates"
 	"bytes"
+	"fmt"
 	"net/http"
 
 	"github.com/google/uuid"
@@ -82,16 +83,22 @@ func registerReaderRoutes(cfg *Config) {
 		})
 		// Convert to template types
 		mediaUUID, _ := uuid.FromBytes(mediaItem.ID.Bytes[0:16])
+		libUUID, _ := uuid.FromBytes(mediaItem.LibraryID.Bytes[0:16])
 		metadata := templates.ReaderMetadata{
-			MediaItemID:    mediaUUID.String(),
-			Title:          mediaItem.Title,
-			Author:         textToString(mediaItem.Author),
-			CoverImagePath: textToString(mediaItem.CoverImagePath),
-			LibraryType:    mediaItem.FormatGroup,
-			MimeType:       textToString(mediaItem.MimeType),
-			FilePath:       mediaItem.FilePath,
-			TotalPages:     int(mediaItem.PageCount.Int32),
-			ChapterCount:   int(mediaItem.ChapterCount.Int32),
+			MediaItemID:      mediaUUID.String(),
+			Title:            mediaItem.Title,
+			Author:           textToString(mediaItem.Author),
+			CoverImagePath:   textToString(mediaItem.CoverImagePath),
+			LibraryType:      mediaItem.FormatGroup,
+			MimeType:         textToString(mediaItem.MimeType),
+			FilePath:         mediaItem.FilePath,
+			TotalPages:       int(mediaItem.PageCount.Int32),
+			ChapterCount:     int(mediaItem.ChapterCount.Int32),
+			FormatGroup:      mediaItem.FormatGroup,
+			MangaType:        textToString(mediaItem.MangaType),
+			ReadingDirection: textToString(mediaItem.ReadingDirection),
+			LibraryID:        libUUID.String(),
+			FileURL:          fmt.Sprintf("/uploads/library-%s/%s", libUUID.String(), mediaItem.FilePath),
 		}
 		// Progress conversion (inline)
 		progressUUID, _ := uuid.FromBytes(progress.ID.Bytes[0:16])