feat(snippets): add universal keyboard snippets with Dynamic Island & Duo integration

[Balajitechlabs]

Description

Adds universal text snippet expansion for external keyboards (Gboard, SwiftKey, physical keyboards) along with display integration across Dynamic Island, Duo camera ring, and a floating pill.

• Dynamic Island Integration:
  • Displays snippet suggestions as a line peek when trigger keywords are typed.
  • Tap: Inserts the snippet into the active field and copies it to the system clipboard.
  • Long-Press: Expands into a detailed card showing snippet title, keyword badge (!keyword), multi-line text preview, and quick action buttons (Insert, Copy, Dismiss).
  • Isolated touch handling so existing Island gestures and plugins are unaffected.
• Duo Camera Ring Integration:
  • Displays an animated drop-down pill below the camera cutout with tap-to-insert support.
• Display Modes & Smart Recommendation:
  • Adds setting to choose where suggestions appear: Floating Pill, Dynamic Island, Duo Ring, or Both.
  • Intelligently recommends the best style based on which display overlays are currently active.
• Universal External Keyboard Support:
  • Space-based auto-expansion and floating pill positioned dynamically above the keyboard.

Type of change

• Bug fix
• New feature
• UI / visual update
• Performance improvement
• Refactoring / cleanup
• Translations
• Build / CI tooling

UI changes

Checklist

Before submitting, please make sure:

• The base branch is set to develop (not main).
• The app builds cleanly locally with ./gradlew assembleDebug.
• Unit tests pass with ./gradlew testDebugUnitTest.
• You tested the changes on a device or emulator (including Shizuku or Root if applicable).
• New preferences use SettingsRepository for keys and getter/setter methods.
• New user-facing settings are registered in FeatureRegistry.kt for search indexing.
• New UI follows the design system in ui/core/ (RoundedCardContainer, IconToggleItem, etc.).
• Strings are added to res/values/strings.xml and drawables use rounded variants (R.drawable.rounded_*).

[sameerasw]

Request changes.

Blockers

1. The feature defaults to on, and the PR adds typeViewTextChanged to the shared accessibility service. Every user's text input in every app starts feeding it with no opt-in. Default it to off.
2. {clipboard} expands into whatever field has focus. The default !quote snippet uses it, so it can leak clipboard contents into the wrong field.
3. replaceKeywordInNode rewrites the whole field with ACTION_SET_TEXT.
   • It wipes formatting and spans.
   • It uses lastIndexOf, so it can replace the wrong occurrence when the cursor isn't at the end.
   • It never checks whether performAction succeeded.
   • expandSnippet relies on the stale lastTypedWord.
4. There is no guard against re-triggering. ACTION_SET_TEXT fires another text-changed event, which can show a suggestion right after expansion.
5. The accessibility handler also receives events from Essentials' own IME, which already expands on space. The same keystroke can expand twice.
6. Keyword matching is inconsistent. The accessibility path is case-sensitive and the IME path is case-insensitive.

Serious
7. SnippetRepository can lose data.

• Writes run concurrently on Dispatchers.IO, so an older save can overwrite a newer one.
• The file is written in place, so a crash can truncate it.
• A corrupt file loads as empty, and the next edit overwrites it.
• Updates should use MutableStateFlow.update.

8. findMatching matches any prefix and any title substring of two or more characters. Ordinary typing triggers suggestions in every app, and snippets also rank first in the IME suggestions.
9. SuggestionEngine uses distinctBy { it.text }, which can drop a snippet whose title equals a dictionary word. The spell-checker callback can also keep stale snippet suggestions from the previous word.
10. showFloatingPill and hideFloatingPill run in separate post blocks on shared state. Rapid events can leave an orphan overlay. activeNode is never released when replaced.
11. The IslandController change makes Line stage tap and long-press call onTap and onLongPress first. This touches the shared gesture path, so existing plugins need a regression check.
12. While a Duo snippet suggestion is active, all ring gestures are swallowed. If nothing hides it, the ring stays dead.

Minor

• Narrating comments and multi-line KDoc on expand and findMatching, against the repo rules.
• The unrelated intent?. to intent. change in ScreenOffAccessibilityService.
• isKeyboardPackage uses contains("keyboard"), which can match non-IME apps.
• Magic numbers for keyboard height and offsets.
• No tests for the expander, matching or replace logic.

[Balajitechlabs]

done 👍🏻 check now :}

[Balajitechlabs]

minor change: should add permission checker and some minor improvements; everything else is fine