feat: add HalStorage (#656)

## Summary

Continue my changes to introduce the HAL infrastructure from
https://github.com/crosspoint-reader/crosspoint-reader/pull/522

This PR touches quite a lot of files, but most of them are just name
changing. It should not have any impacts to the end behavior.

## Additional Context

My plan is to firstly add this small shim layer, which sounds useless at
first, but then I'll implement an emulated driver which can be helpful
for testing and for development.

Currently, on my fork, I'm using a FS driver that allow "mounting" a
local directory from my computer to the device, much like the `-v` mount
option on docker. This allows me to quickly reset `.crosspoint`
directory if anything goes wrong. I plan to upstream this feature when
this PR get merged.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? NO

lib/Txt/Txt.cpp

@@ -15,13 +15,13 @@ bool Txt::load() {
     return true;
   }
 
-  if (!SdMan.exists(filepath.c_str())) {
+  if (!Storage.exists(filepath.c_str())) {
     Serial.printf("[%lu] [TXT] File does not exist: %s\n", millis(), filepath.c_str());
     return false;
   }
 
   FsFile file;
-  if (!SdMan.openFileForRead("TXT", filepath, file)) {
+  if (!Storage.openFileForRead("TXT", filepath, file)) {
     Serial.printf("[%lu] [TXT] Failed to open file: %s\n", millis(), filepath.c_str());
     return false;
   }
@@ -48,11 +48,11 @@ std::string Txt::getTitle() const {
 }
 
 void Txt::setupCacheDir() const {
-  if (!SdMan.exists(cacheBasePath.c_str())) {
-    SdMan.mkdir(cacheBasePath.c_str());
+  if (!Storage.exists(cacheBasePath.c_str())) {
+    Storage.mkdir(cacheBasePath.c_str());
   }
-  if (!SdMan.exists(cachePath.c_str())) {
-    SdMan.mkdir(cachePath.c_str());
+  if (!Storage.exists(cachePath.c_str())) {
+    Storage.mkdir(cachePath.c_str());
   }
 }
 
@@ -73,7 +73,7 @@ std::string Txt::findCoverImage() const {
   // First priority: look for image with same name as txt file (e.g., mybook.jpg)
   for (const auto& ext : extensions) {
     std::string coverPath = folder + "/" + baseName + ext;
-    if (SdMan.exists(coverPath.c_str())) {
+    if (Storage.exists(coverPath.c_str())) {
       Serial.printf("[%lu] [TXT] Found matching cover image: %s\n", millis(), coverPath.c_str());
       return coverPath;
     }
@@ -84,7 +84,7 @@ std::string Txt::findCoverImage() const {
   for (const auto& name : coverNames) {
     for (const auto& ext : extensions) {
       std::string coverPath = folder + "/" + std::string(name) + ext;
-      if (SdMan.exists(coverPath.c_str())) {
+      if (Storage.exists(coverPath.c_str())) {
         Serial.printf("[%lu] [TXT] Found fallback cover image: %s\n", millis(), coverPath.c_str());
         return coverPath;
       }
@@ -98,7 +98,7 @@ std::string Txt::getCoverBmpPath() const { return cachePath + "/cover.bmp"; }
 
 bool Txt::generateCoverBmp() const {
   // Already generated, return true
-  if (SdMan.exists(getCoverBmpPath().c_str())) {
+  if (Storage.exists(getCoverBmpPath().c_str())) {
     return true;
   }
 
@@ -122,10 +122,10 @@ bool Txt::generateCoverBmp() const {
     // Copy BMP file to cache
     Serial.printf("[%lu] [TXT] Copying BMP cover image to cache\n", millis());
     FsFile src, dst;
-    if (!SdMan.openFileForRead("TXT", coverImagePath, src)) {
+    if (!Storage.openFileForRead("TXT", coverImagePath, src)) {
       return false;
     }
-    if (!SdMan.openFileForWrite("TXT", getCoverBmpPath(), dst)) {
+    if (!Storage.openFileForWrite("TXT", getCoverBmpPath(), dst)) {
       src.close();
       return false;
     }
@@ -144,10 +144,10 @@ bool Txt::generateCoverBmp() const {
     // Convert JPG/JPEG to BMP (same approach as Epub)
     Serial.printf("[%lu] [TXT] Generating BMP from JPG cover image\n", millis());
     FsFile coverJpg, coverBmp;
-    if (!SdMan.openFileForRead("TXT", coverImagePath, coverJpg)) {
+    if (!Storage.openFileForRead("TXT", coverImagePath, coverJpg)) {
       return false;
     }
-    if (!SdMan.openFileForWrite("TXT", getCoverBmpPath(), coverBmp)) {
+    if (!Storage.openFileForWrite("TXT", getCoverBmpPath(), coverBmp)) {
       coverJpg.close();
       return false;
     }
@@ -157,7 +157,7 @@ bool Txt::generateCoverBmp() const {
 
     if (!success) {
       Serial.printf("[%lu] [TXT] Failed to generate BMP from JPG cover image\n", millis());
-      SdMan.remove(getCoverBmpPath().c_str());
+      Storage.remove(getCoverBmpPath().c_str());
     } else {
       Serial.printf("[%lu] [TXT] Generated BMP from JPG cover image\n", millis());
     }
@@ -175,7 +175,7 @@ bool Txt::readContent(uint8_t* buffer, size_t offset, size_t length) const {
   }
 
   FsFile file;
-  if (!SdMan.openFileForRead("TXT", filepath, file)) {
+  if (!Storage.openFileForRead("TXT", filepath, file)) {
     return false;
   }
 

lib/Txt/Txt.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <memory>
 #include <string>