# Port Upstream PRs #997, #1003, #1005, #1010

## Task
Cherry-pick / port four upstream PRs from crosspoint-reader/crosspoint-reader into the mod fork.

## Changes Made

### PR #997 -- Already Ported (no changes)
Glyph null-safety in `getSpaceWidth`/`getTextAdvanceX` was already present via commit `c1b8e53`.

### PR #1010 -- Fix Dangling Pointer
- **src/main.cpp**: `onGoToReader()` now copies the `initialEpubPath` string before calling `exitActivity()`, preventing a dangling reference when the owning activity is destroyed.

### PR #1005 -- Use HalPowerManager for Battery Percentage
- **lib/hal/HalPowerManager.h**: Changed `getBatteryPercentage()` return type from `int` to `uint16_t`.
- **lib/hal/HalPowerManager.cpp**: Same return type change.
- **src/Battery.h**: Emptied contents (was `static BatteryMonitor battery(BAT_GPIO0)`).
- **src/main.cpp**: Removed `#include "Battery.h"`.
- **src/activities/home/HomeActivity.cpp**: Removed `#include "Battery.h"`.
- **src/components/themes/BaseTheme.cpp**: Replaced `Battery.h` include with `HalPowerManager.h`, replaced `battery.readPercentage()` with `powerManager.getBatteryPercentage()` (2 occurrences).
- **src/components/themes/lyra/LyraTheme.cpp**: Same replacements (2 occurrences).

### PR #1003 -- Render Image Placeholders While Waiting for Decode
- **lib/Epub/Epub/blocks/ImageBlock.h/.cpp**: Added `isCached()` method that checks if the `.pxc` cache file exists.
- **lib/Epub/Epub/Page.h/.cpp**: Added `PageImage::isCached()`, `PageImage::renderPlaceholder()`, `Page::renderTextOnly()`, `Page::countUncachedImages()`, `Page::renderImagePlaceholders()`. Added `#include <GfxRenderer.h>` to Page.h.
- **src/activities/reader/EpubReaderActivity.cpp**: Modified `renderContents()` to check for uncached images and display text + placeholder rectangles immediately (Phase 1 with HALF_REFRESH), then proceed with full image decode and display (Phase 2 with fast refresh). Existing mod-specific double FAST_REFRESH logic for anti-aliased image pages is preserved for the cached-image path.

## Build Result
SUCCESS -- RAM: 31.5%, Flash: 70.4%. No linter errors.

## Follow-up Items
- PR #1003 is still open upstream (not merged); may need to rebase if upstream changes before merge.
- The phased rendering for uncached images skips the mod's double FAST_REFRESH technique (relies on Phase 1's HALF_REFRESH instead). If grayscale quality on first-decode image pages is suboptimal, this could be revisited.