fix: Reduce flash usage by cleaning up I18n translations (#1401)

## Summary

* **What is the goal of this PR?** 
Removing no longer used i18n keys/string, to reduce (~28k) used flash
space.
To correct to swedish translations for `STR_FONT_SIZE` and
`STR_KOREADER_SYNC`.

* **What changes are included?**
   `lib\I18n\translations\*`

## Additional Context

* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks,
  specific areas to focus on).

---

### 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/I18n/translations/english.yaml

@@ -9,11 +9,9 @@ STR_ENTERING_SLEEP: "Going to sleep"
 STR_BROWSE_FILES: "Browse Files"
 STR_FILE_TRANSFER: "File Transfer"
 STR_SETTINGS_TITLE: "Settings"
-STR_CALIBRE_LIBRARY: "Calibre Library"
 STR_CONTINUE_READING: "Continue Reading"
 STR_NO_OPEN_BOOK: "No open book"
 STR_START_READING: "Start reading below"
-STR_BOOKS: "Books"
 STR_NO_FILES_FOUND: "No files found"
 STR_SELECT_CHAPTER: "Select Chapter"
 STR_NO_CHAPTERS: "No chapters"
@@ -26,10 +24,6 @@ STR_EMPTY_FILE: "Empty file"
 STR_OUT_OF_BOUNDS: "Out of bounds"
 STR_LOADING: "Loading..."
 STR_LOADING_POPUP: "Loading"
-STR_LOAD_XTC_FAILED: "Failed to load XTC"
-STR_LOAD_TXT_FAILED: "Failed to load TXT"
-STR_LOAD_EPUB_FAILED: "Failed to load EPUB"
-STR_SD_CARD_ERROR: "SD card error"
 STR_WIFI_NETWORKS: "WiFi Networks"
 STR_NO_NETWORKS: "No networks found"
 STR_NETWORKS_FOUND: "%zu networks found"
@@ -37,14 +31,9 @@ STR_SCANNING: "Scanning..."
 STR_CONNECTING: "Connecting..."
 STR_CONNECTED: "Connected!"
 STR_CONNECTION_FAILED: "Connection Failed"
-STR_CONNECTION_TIMEOUT: "Connection timeout"
 STR_FORGET_NETWORK: "Forget Network?"
 STR_SAVE_PASSWORD: "Save password for next time?"
-STR_REMOVE_PASSWORD: "Remove saved password?"
 STR_PRESS_OK_SCAN: "Press OK to scan again"
-STR_PRESS_ANY_CONTINUE: "Press any button to continue"
-STR_SELECT_HINT: "LEFT/RIGHT: Select | OK: Confirm"
-STR_HOW_CONNECT: "How would you like to connect?"
 STR_JOIN_NETWORK: "Join a Network"
 STR_CREATE_HOTSPOT: "Create Hotspot"
 STR_JOIN_DESC: "Connect to an existing WiFi network"
@@ -57,27 +46,13 @@ STR_OR_HTTP_PREFIX: "or http://"
 STR_SCAN_QR_HINT: "or scan QR code with your phone:"
 STR_CALIBRE_WIRELESS: "Calibre Wireless"
 STR_CALIBRE_WEB_URL: "Calibre Web URL"
-STR_CONNECT_WIRELESS: "Connect as Wireless Device"
 STR_NETWORK_LEGEND: "* = Encrypted | + = Saved"
 STR_MAC_ADDRESS: "MAC address:"
 STR_CHECKING_WIFI: "Checking WiFi..."
 STR_ENTER_WIFI_PASSWORD: "Enter WiFi Password"
-STR_ENTER_TEXT: "Enter Text"
 STR_TO_PREFIX: "to "
-STR_CALIBRE_DISCOVERING: "Discovering Calibre..."
-STR_CALIBRE_CONNECTING_TO: "Connecting to "
-STR_CALIBRE_CONNECTED_TO: "Connected to "
-STR_CALIBRE_WAITING_COMMANDS: "Waiting for commands..."
-STR_CONNECTION_FAILED_RETRYING: "(Connection failed, retrying)"
-STR_CALIBRE_DISCONNECTED: "Calibre disconnected"
-STR_CALIBRE_WAITING_TRANSFER: "Waiting for transfer..."
-STR_CALIBRE_TRANSFER_HINT: "If transfer fails, enable\\n'Ignore free space' in Calibre's\\nSmartDevice plugin settings."
 STR_CALIBRE_RECEIVING: "Receiving: "
 STR_CALIBRE_RECEIVED: "Received: "
-STR_CALIBRE_WAITING_MORE: "Waiting for more..."
-STR_CALIBRE_FAILED_CREATE_FILE: "Failed to create file"
-STR_CALIBRE_PASSWORD_REQUIRED: "Password required"
-STR_CALIBRE_TRANSFER_INTERRUPTED: "Transfer interrupted"
 STR_CALIBRE_INSTRUCTION_1: "1) Install CrossPoint Reader plugin"
 STR_CALIBRE_INSTRUCTION_2: "2) Be on the same WiFi network"
 STR_CALIBRE_INSTRUCTION_3: "3) In Calibre: \"Send to device\""
@@ -88,7 +63,6 @@ STR_CAT_CONTROLS: "Controls"
 STR_CAT_SYSTEM: "System"
 STR_SLEEP_SCREEN: "Sleep Screen"
 STR_SLEEP_COVER_MODE: "Sleep Screen Cover Mode"
-STR_STATUS_BAR: "Status Bar"
 STR_HIDE_BATTERY: "Hide Battery %"
 STR_EXTRA_SPACING: "Extra Paragraph Spacing"
 STR_TEXT_AA: "Text Anti-Aliasing"
@@ -98,32 +72,21 @@ STR_IMAGES_PLACEHOLDER: "Placeholder"
 STR_IMAGES_SUPPRESS: "Suppress"
 STR_SHORT_PWR_BTN: "Short Power Button Click"
 STR_ORIENTATION: "Reading Orientation"
-STR_FRONT_BTN_LAYOUT: "Front Button Layout"
 STR_SIDE_BTN_LAYOUT: "Side Button Layout (reader)"
 STR_LONG_PRESS_SKIP: "Long-press Chapter Skip"
 STR_FONT_FAMILY: "Reader Font Family"
-STR_EXT_READER_FONT: "External Reader Font"
-STR_EXT_CHINESE_FONT: "Reader Font"
-STR_EXT_UI_FONT: "UI Font"
 STR_FONT_SIZE: "Reader Font Size"
 STR_LINE_SPACING: "Reader Line Spacing"
-STR_ASCII_LETTER_SPACING: "ASCII Letter Spacing"
-STR_ASCII_DIGIT_SPACING: "ASCII Digit Spacing"
-STR_CJK_SPACING: "CJK Spacing"
-STR_COLOR_MODE: "Color Mode"
 STR_SCREEN_MARGIN: "Reader Screen Margin"
 STR_PARA_ALIGNMENT: "Reader Paragraph Alignment"
 STR_HYPHENATION: "Hyphenation"
 STR_TIME_TO_SLEEP: "Time to Sleep"
 STR_SHOW_HIDDEN_FILES: "Show Hidden Files"
 STR_REFRESH_FREQ: "Refresh Frequency"
-STR_CALIBRE_SETTINGS: "Calibre Settings"
 STR_KOREADER_SYNC: "KOReader Sync"
 STR_CHECK_UPDATES: "Check for updates"
 STR_LANGUAGE: "Language"
-STR_SELECT_WALLPAPER: "Select Wallpaper"
 STR_CLEAR_READING_CACHE: "Clear Reading Cache"
-STR_CALIBRE: "Calibre"
 STR_USERNAME: "Username"
 STR_PASSWORD: "Password"
 STR_SYNC_SERVER_URL: "Sync Server URL"
@@ -158,8 +121,6 @@ STR_COVER: "Cover"
 STR_NONE_OPT: "None"
 STR_FIT: "Fit"
 STR_CROP: "Crop"
-STR_NO_PROGRESS: "No Progress"
-STR_FULL_OPT: "Full"
 STR_NEVER: "Never"
 STR_IN_READER: "In Reader"
 STR_ALWAYS: "Always"
@@ -170,9 +131,6 @@ STR_PORTRAIT: "Portrait"
 STR_LANDSCAPE_CW: "Landscape CW"
 STR_INVERTED: "Inverted"
 STR_LANDSCAPE_CCW: "Landscape CCW"
-STR_FRONT_LAYOUT_BCLR: "Bck, Cnfrm, Lft, Rght"
-STR_FRONT_LAYOUT_LRBC: "Lft, Rght, Bck, Cnfrm"
-STR_FRONT_LAYOUT_LBCR: "Lft, Bck, Cnfrm, Rght"
 STR_PREV_NEXT: "Prev/Next"
 STR_NEXT_PREV: "Next/Prev"
 STR_BOOKERLY: "Bookerly"
@@ -209,8 +167,6 @@ STR_NO_UPDATE: "No update available"
 STR_UPDATE_FAILED: "Update failed"
 STR_UPDATE_COMPLETE: "Update complete"
 STR_POWER_ON_HINT: "Press and hold power button to turn back on"
-STR_EXTERNAL_FONT: "External Font"
-STR_BUILTIN_DISABLED: "Built-in (Disabled)"
 STR_NO_ENTRIES: "No entries found"
 STR_DOWNLOADING: "Downloading..."
 STR_DOWNLOAD_FAILED: "Download failed"
@@ -221,7 +177,6 @@ STR_FETCH_FEED_FAILED: "Failed to fetch feed"
 STR_PARSE_FEED_FAILED: "Failed to parse feed"
 STR_NETWORK_PREFIX: "Network: "
 STR_IP_ADDRESS_PREFIX: "IP Address: "
-STR_SCAN_QR_WIFI_HINT: "or scan QR code with your phone to connect to Wifi."
 STR_ERROR_GENERAL_FAILURE: "Error: General failure"
 STR_ERROR_NETWORK_NOT_FOUND: "Error: Network not found"
 STR_ERROR_CONNECTION_TIMEOUT: "Error: Connection timeout"
@@ -229,7 +184,6 @@ STR_SD_CARD: "SD card"
 STR_BACK: "« Back"
 STR_EXIT: "« Exit"
 STR_HOME: "« Home"
-STR_SAVE: "« Save"
 STR_SELECT: "Select"
 STR_SELECTED: "Selected"
 STR_TOGGLE: "Toggle"
@@ -250,8 +204,6 @@ STR_DIR_LEFT: "Left"
 STR_DIR_RIGHT: "Right"
 STR_DIR_UP: "Up"
 STR_DIR_DOWN: "Down"
-STR_CAPS_ON: "CAPS"
-STR_CAPS_OFF: "caps"
 STR_OK_BUTTON: "OK"
 STR_SLEEP_COVER_FILTER: "Sleep Screen Cover Filter"
 STR_FILTER_CONTRAST: "Contrast"
@@ -278,7 +230,6 @@ STR_SUNLIGHT_FADING_FIX: "Sunlight Fading Fix"
 STR_REMAP_FRONT_BUTTONS: "Remap Front Buttons"
 STR_OPDS_BROWSER: "OPDS Browser"
 STR_COVER_CUSTOM: "Cover + Custom"
-STR_RECENTS: "Recents"
 STR_MENU_RECENT_BOOKS: "Recent Books"
 STR_NO_RECENT_BOOKS: "No recent books"
 STR_CALIBRE_DESC: "Use Calibre wireless device transfers"
@@ -307,9 +258,6 @@ STR_DISPLAY_QR: "Show page as QR"
 STR_CHAPTER_PREFIX: "Chapter: "
 STR_PAGES_SEPARATOR: " pages  |  "
 STR_BOOK_PREFIX: "Book: "
-STR_KBD_SHIFT: "shift"
-STR_KBD_SHIFT_CAPS: "SHIFT"
-STR_KBD_LOCK: "LOCK"
 STR_CALIBRE_URL_HINT: "For Calibre, add /opds to your URL"
 STR_PERCENT_STEP_HINT: "Left/Right: 1%  Up/Down: 10%"
 STR_SYNCING_TIME: "Syncing time..."