Migrate themes to SD card

[anarchyysm]

Problem

Goal: the 12 themes move out of screen_themes.conf on flash and live in themes/*/theme.conf on SD.
Estimated effort: 2 days

Proposed Solution

• Create Service/storage_api/include/tos_theme.h
• Create Service/storage_api/tos_theme.c
• Implement theme.conf parser (sections [meta], [colors], [protocol_colors])
• Implement 0xRRGGBB hex → lv_color_t conversion
• Implement color application to global lv_style_t
• Implement tos_theme_set_active_protocol(protocol) to swap border_accent for the protocol color
• Implement fallback: if theme.conf on SD fails, read screen_themes.conf from flash
• Convert all 12 existing themes from screen_themes.conf to the theme.conf folder format:
  • themes/default/theme.conf
  • themes/matrix/theme.conf
  • themes/cyber_blue/theme.conf
  • themes/blood/theme.conf
  • themes/toxic/theme.conf
  • themes/ghost/theme.conf
  • themes/neon_pink/theme.conf
  • themes/amber/theme.conf
  • themes/terminal/theme.conf
  • themes/ice/theme.conf
  • themes/deep_purple/theme.conf
  • themes/midnight/theme.conf
• Add the 7 protocol_* tokens to each theme.conf (can use border_accent value as initial default)
• Implement automatic migration in first_boot_setup(): if themes/ is empty, copy the 12 themes from flash to SD
• Test: ls /sdcard/themes/ returns 12 directories
• Test: manually change theme in config/screen.conf and reboot — screens reflect the new colors

Use Case

No response

Alternatives Considered

No response