feat(input): add optional per-field Literal typing mode

[AsafMah]

Summary

Add an optional Literal typing action for URLs, code, and other text that should stay as typed. Enable the action in Settings → Toolbar → Toolbar keys or Pinned toolbar keys; it is not forced into existing enabled layouts. Tap once to enable it for the current field, and again to restore normal typing. Custom layouts can use {"label":"literal"} or keycode -10078 (TOGGLE_LITERAL_MODE).

The state belongs to the active LatinIME/editor session, not saved preferences. New fields, input finish, and service destruction reset it; hiding the keyboard and identifiable same-editor restarts retain it. Ambiguous zero-ID restarts reset conservatively.

Behavior

• Suppress automatic capitalization (including Force), correction (including per-app force-enable), predictions/application completions, automatic spacing and double-space periods, text expansions, dictionary learning, and word-glide typing.
• Preserve explicitly typed case/manual Shift, script composition such as Hangul, editing actions, paste, emoji insertion, and the editor's Enter action. This does not globally disable editing gestures.
• Finish pending composition as typed on toggle, without correction or cursor movement; clear pending automatic-spacing state and reject stale worker/UI suggestion results, including on → off races.
• Keep toolbar and pinned activation in sync without a preference event; the existing auto-correction action reflects the effective setting. Stored typing preferences and learned history are not changed or deleted; in particular, personalized dictionaries are not disabled to suppress learning.

This is an explicit optional mode, not automatic URL/code detection or a general fix for unknown capitalization/contraction behavior. No changes to RichInputConnection, contraction ranking, GIF/media support, platform dependencies, or minSDK.

Validation

On JDK 21 with the existing Android SDK, the focused :app:testStandardDebugUnitTest run passed: 107 passed, 1 existing ignored Hangul test. Scope: all 100 InputLogic tests (99 passed), both new Literal JSON/numeric/popup parser cases, the existing toolbar-popup parser case, and 5 settings tests. The Literal cases exercise actual owner lifecycle/reset/destroy, settings reload and per-app forced correction, composing text/cursor preservation, Hangul, explicit case/paste/emoji/TLD text, toolbar+pinned click dispatch/activation, learning suppression, and queued/running stale-result rejection.

A broader run also executed all ParserTest cases: 8 existing layout-asset lookup failures (NoSuchElementException in LayoutUtils.getContent). All eight were reproduced with the same method names and messages on an untouched detached checkout of base b718d832c41ba01e1cce613f14e6209c279e9d17 (46 parser tests at base; 48 with this feature). No tests, baselines, or production asset behavior were relaxed to hide them. No APK build, native-glide library execution, or phone/device testing is claimed.

Port scope

One independent commit on upstream b718d832c41ba01e1cce613f14e6209c279e9d17, adapted from source feature 998dbcb56591dc1b0cc2f8ebb828c816dade186a. All added/removed production lines match that immutable feature exactly. Port-only adjustments: omit the fork-only row-swipe test; add its missing expansion-test setup helper/import using existing upstream APIs; add two focused Literal parser tests and usage/keycode documentation. No other fork commits or sibling PRs are required.