feat(input): add textInputRef to reach the TextInput

[bataevvlad]

Problem

Input's ref is the InputRef API (focus / blur / isFocused / clear), so a library that expects a React Native TextInput (setNativeProps, measure, react-phone-number-input's inputComponent) cannot use it. Same for Autocomplete.

Fix

• Input gains textInputRef?: React.Ref<TextInput>, forwarded to the underlying TextInput through a callback ref that also feeds the internal ref, so the InputRef API keeps working alongside it. Object and callback refs are both supported.
• Autocomplete extends InputProps and spreads them onto its Input, so textInputRef reaches the native input; documented on both components.
• Showcase InputNativeRef (end of SHOWCASES): an Input and an Autocomplete with native refs; the probe button reports both ref types and calls setNativeProps({ text }) on the Input's node. Docs rows in input.mdx and autocomplete.mdx. No story: nothing visual.

Verification

• Specs (3 new, all fail on master): input.spec.tsx object ref and callback ref receive the TextInput instance while InputRef still works; autocomplete.spec.tsx textInputRef receives the TextInput.
• Android emulator (Pixel 7, Eva light, section-InputNativeRef): pressing the probe shows "native refs: input TextInput, autocomplete TextInput" and the Input's text becomes "set through setNativeProps".
• iOS simulator and yarn e2e:ios: see "iOS verification (2026-09-28)" below.
• Gates: yarn turbo run build --filter=@ui-kitten/components, yarn typecheck:all, yarn lint (0 errors, 50 pre-existing warnings), yarn test --runInBand (74 suites, 1889 tests) pass.

Changeset: @ui-kitten/components minor.

Closes #1520

iOS verification (2026-09-28)

iPhone 17 simulator (iOS 26.2), debug build on Metro from a clean worktree of this branch, driven with agent-device.

• section-InputNativeRef: the probe reports native refs: input TextInput, autocomplete TextInput and the Input shows set through setNativeProps.
• Old Input section: typing still works; old Autocomplete section: typing st shows Star Wars / Interstellar, picking Star Wars fills the field.
• yarn e2e:ios against a Metro serving this branch (the flags injected into a scratch copy of the scripts; without them agent-device test loads the bundle from :8081): smoke.ad and icon-touchable.ad pass; modal-nested.ad (step 51) and autocomplete.ad fail exactly as on master (both fixed in test(e2e): keep modals inside the snapshot budget #1918). An earlier run reported here had loaded another checkout's bundle from :8081 and did not test this branch.

Android verification (2026-09-28, second pass)

Pixel 7 emulator (API 34), debug build on Metro from a clean worktree of this branch, driven with agent-device.

• section-InputNativeRef: probe -> native refs: input TextInput, autocomplete TextInput, Input text set through setNativeProps; the Autocomplete with textInputRef filters on typing.
• Old Input typing and old Autocomplete (fill st -> Star Wars / Interstellar, pick Star Wars) work. A plain tap on an Autocomplete opens the list without the keyboard (keyboard on the second tap): identical on master, pre-existing.
• popover-android.ad is stale on master (its fixed scroll count stops at the List section) and was not a branch check; test(e2e): reach showcase sections through a deep link #1932 replaces the scrolls with a section deep link. The Android replay line previously reported here had also loaded another checkout's bundle from :8081.