feat: implement auto-spacing after punctuation and double-tap space period (#669)

[prince-0408]

Description

This PR implements two standard soft-keyboard usability features as requested in #669 by adding automatic punctuation spacing and refining double-tap space for period behavior to align with modern keyboard standards (such as Gboard and SwiftKey).

Key Changes

Double-Tap Space for Period (. ):

• Updated SpaceKeyProcessor.kt so that pressing the spacebar twice after a word converts the trailing space to a period and space (. ).
• Automatically activates single-character shift state (SHIFT_ON_ONE_CHAR) on period conversion to capitalize the first letter of the next sentence.
• Removed outdated helper functions to simplify and streamline spacebar event handling.

Auto-Spacing After Punctuation:

• Updated KeyHandler.kt to intercept punctuation keys (., ,, !, ?) and automatically append a trailing space when typed after a word.
• Handled edge cases to gracefully remove auto-inserted spaces if a consecutive punctuation mark (e.g. ... or ?!) or backspace is typed.

Settings & Preferences Integration:

• Added AUTO_SPACE_AFTER_PUNCTUATION constant, getter, and setter in PreferencesHelper.kt.
• Defaulted both "Double-space for period" and "Auto-space after punctuation" settings to enabled (true).
• Added a new toggle switch for "Auto-space after punctuation" under Keyboard Settings > Functionality in LanguageSettingsScreen.kt.
• Added string resources in en-US/string.xml.

Unit Tests & Linter Cleanliness:

• Added new test coverage in SpaceKeyProcessorTest.kt for spacebar event processing and period commits.
• Formatted all Kotlin sources via ./gradlew formatKotlin to ensure clean compliance with ktlint and detekt.

Visual Demonstration

Related Issue

Closes #669

[andrewtavis]

Thanks for the PR, @prince-0408! Could we do one quick PR to Scribe-i18n to add in the needed strings for this menu option? Then we can merge that and rebase this PR?

[prince-0408]

Thanks for the PR, @prince-0408! Could we do one quick PR to Scribe-i18n to add in the needed strings for this menu option? Then we can merge that and rebase this PR?

Hi @andrewtavis! 👋

I have opened the PR to Scribe-i18n with the required string keys here:
👉 scribe-org/Scribe-i18n#122

CI Status & Fallback Implementation:

• Temporary Fallback Strings: Added the string definitions directly into app/src/main/res/values/strings.xml (plural) as a fallback. Since moveFromi18n only overwrites singular string.xml during Gradle preBuild, adding them to strings.xml ensures AAPT2 merges the resources and keeps all 6 Android CI checks 100% green while #122 is being reviewed.
• Upstream Sync: Updated this branch with the latest changes from scribe-org/main.

Once Scribe-i18n#122 is merged into main, I will update the app/src/main/assets/i18n submodule pointer to the new commit and clean up the fallback entries from strings.xml.

[andrewtavis]

Thanks, @prince-0408! See my comment here asking if we want to expand this a bit :) I'm happy to finalize the changes to Scribe-i18n if you verify that it makes sense, and from there we can bring those strings in and finish this up too 😊

[andrewtavis]

Scribe-i18n has been updated now, @prince-0408, so feel free to sync this and I'll look further 😊

[prince-0408]

Scribe-i18n has been updated now, @prince-0408, so feel free to sync this and I'll look further 😊

Hi @andrewtavis

I have synced the i18n submodule to point to the merged scribe-org/Scribe-i18n:main commit!

I also cleaned up the temporary fallback entries from strings.xml to prevent AAPT resource duplication issues during build.

All checks are running and ready for your review whenever you have a moment. Thanks! 😊