My Library: Tab bar w/ Recent Books + File Browser (#250)

# Summary

This PR introduces a reusable Tab Bar component and combines the Recent
Books and File Browser into a unified tabbed page called "My Library"
accessible from the Home screen.

## Features
### New Tab Bar Component
A flexible, reusable tab bar component added to `ScreenComponents` that
can be used throughout the application.

### New Scroll Indicator Component
A page position indicator for lists that span multiple pages.
**Features:**
- Up/down arrow indicators
- Current page fraction display (e.g., "1/3")
- Only renders when content spans multiple pages

### My Library Activity
A new unified view combining Recent Books and File Browser into a single
tabbed page.

**Tabs:**
- **Recent** - Shows recently opened books
- **Files** - Browse SD card directory structure

**Navigation:**
- Up/Down or Left/Right: Navigate through list items
- Left/Right (when first item selected): Switch between tabs
- Confirm: Open selected book or enter directory
- Back: Go up directory (Files tab) or return home
- Long press Back: Jump to root directory (Files tab)

**UI Elements:**
- Tab bar with selection indicator
- Scroll/page indicator on right side
- Side button hints (up/down arrows)
- Dynamic bottom button labels ("BACK" in subdirectories, "HOME" at
root)

## Tab Bar Usage
The tab bar component is designed to be reusable across different
activities. Here's how to use it:

### Basic Example
```cpp
#include "ScreenComponents.h"
void MyActivity::render() const {
  renderer.clearScreen();
  
  // Define tabs with labels and selection state
  std::vector<TabInfo> tabs = {
    {"Tab One", currentTab == 0},   // Selected when currentTab is 0
    {"Tab Two", currentTab == 1},   // Selected when currentTab is 1
    {"Tab Three", currentTab == 2}  // Selected when currentTab is 2
  };
  
  // Draw tab bar at Y position 15, returns height of the tab bar
  int tabBarHeight = ScreenComponents::drawTabBar(renderer, 15, tabs);
  
  // Position your content below the tab bar
  int contentStartY = 15 + tabBarHeight + 10; // Add some padding
  
  // Draw content based on selected tab
  if (currentTab == 0) {
    renderTabOneContent(contentStartY);
  } else if (currentTab == 1) {
    renderTabTwoContent(contentStartY);
  } else {
    renderTabThreeContent(contentStartY);
  }
  
  renderer.displayBuffer();
}
```
Video Demo: https://share.cleanshot.com/P6NBncFS

<img width="250"
src="https://github.com/user-attachments/assets/07de4418-968e-4a88-9b42-ac5f53d8a832"
/>
<img width="250"
src="https://github.com/user-attachments/assets/e40201ed-dcc8-4568-b008-cd2bf13ebb2a"
/>
<img width="250"
src="https://github.com/user-attachments/assets/73db269f-e629-4696-b8ca-0b8443451a05"
/>

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

src/main.cpp

@@ -14,10 +14,12 @@
 #include "CrossPointState.h"
 #include "KOReaderCredentialStore.h"
 #include "MappedInputManager.h"
+#include "RecentBooksStore.h"
 #include "activities/boot_sleep/BootActivity.h"
 #include "activities/boot_sleep/SleepActivity.h"
 #include "activities/browser/OpdsBookBrowserActivity.h"
 #include "activities/home/HomeActivity.h"
+#include "activities/home/MyLibraryActivity.h"
 #include "activities/network/CrossPointWebServerActivity.h"
 #include "activities/reader/ReaderActivity.h"
 #include "activities/settings/SettingsActivity.h"
@@ -211,12 +213,13 @@ void enterDeepSleep() {
 }
 
 void onGoHome();
-void onGoToReader(const std::string& initialEpubPath) {
+void onGoToMyLibraryWithTab(const std::string& path, MyLibraryActivity::Tab tab);
+void onGoToReader(const std::string& initialEpubPath, MyLibraryActivity::Tab fromTab) {
   exitActivity();
-  enterNewActivity(new ReaderActivity(renderer, mappedInputManager, initialEpubPath, onGoHome));
+  enterNewActivity(
+      new ReaderActivity(renderer, mappedInputManager, initialEpubPath, fromTab, onGoHome, onGoToMyLibraryWithTab));
 }
-void onGoToReaderHome() { onGoToReader(std::string()); }
-void onContinueReading() { onGoToReader(APP_STATE.openEpubPath); }
+void onContinueReading() { onGoToReader(APP_STATE.openEpubPath, MyLibraryActivity::Tab::Recent); }
 
 void onGoToFileTransfer() {
   exitActivity();
@@ -228,6 +231,16 @@ void onGoToSettings() {
   enterNewActivity(new SettingsActivity(renderer, mappedInputManager, onGoHome));
 }
 
+void onGoToMyLibrary() {
+  exitActivity();
+  enterNewActivity(new MyLibraryActivity(renderer, mappedInputManager, onGoHome, onGoToReader));
+}
+
+void onGoToMyLibraryWithTab(const std::string& path, MyLibraryActivity::Tab tab) {
+  exitActivity();
+  enterNewActivity(new MyLibraryActivity(renderer, mappedInputManager, onGoHome, onGoToReader, tab, path));
+}
+
 void onGoToBrowser() {
   exitActivity();
   enterNewActivity(new OpdsBookBrowserActivity(renderer, mappedInputManager, onGoHome));
@@ -235,7 +248,7 @@ void onGoToBrowser() {
 
 void onGoHome() {
   exitActivity();
-  enterNewActivity(new HomeActivity(renderer, mappedInputManager, onContinueReading, onGoToReaderHome, onGoToSettings,
+  enterNewActivity(new HomeActivity(renderer, mappedInputManager, onContinueReading, onGoToMyLibrary, onGoToSettings,
                                     onGoToFileTransfer, onGoToBrowser));
 }
 
@@ -304,6 +317,8 @@ void setup() {
   enterNewActivity(new BootActivity(renderer, mappedInputManager));
 
   APP_STATE.loadFromFile();
+  RECENT_BOOKS.loadFromFile();
+
   if (APP_STATE.openEpubPath.empty()) {
     onGoHome();
   } else {
@@ -312,7 +327,7 @@ void setup() {
     APP_STATE.openEpubPath = "";
     APP_STATE.lastSleepImage = 0;
     APP_STATE.saveToFile();
-    onGoToReader(path);
+    onGoToReader(path, MyLibraryActivity::Tab::Recent);
   }
 
   // Ensure we're not still holding the power button before leaving setup