docs: add Screen Reader Speed to PRODUCT.md and ARCHITECTURE.md

[Copilot]

PR #33 introduced a screenReaderSpeed accessibility setting (uint8_t, 0–255) with a new OnScreenReaderSpeedChanged event handler and USERSETTINGS_SCREEN_READER_SPEED_KEY constant, but documentation was not updated.

Changes

• PRODUCT.md — Added screen reader speed to the Accessibility Features list
• ARCHITECTURE.md — Added screen reader speed to the Accessibility Settings list; bumped managed settings count 18 → 19

SME validation recommended: confirm the platform-meaningful range and default value for screenReaderSpeed (typed as uint8_t, documented as 0–255).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/graphql
  • Triggering command: /usr/bin/gh gh repo view --json parent --jq .parent | "\(.owner.login)/\(.name)" (http block)
  • Triggering command: /usr/bin/gh gh repo view melhar098/entservices-usersettings --json parent --jq .parent | "\(.owner.login)/\(.name)" (http block)
  • Triggering command: /usr/bin/gh gh repo view rdkcentral/entservices-usersettings --json nameWithOwner,viewerPermission (http block)
• https://api.github.com/repos/rdkcentral/entservices-usersettings
  • Triggering command: /usr/bin/curl curl -s -o /dev/null -w %{http_code} -H Authorization: ****** REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)