feat(tui): support mouse text selection in prompt editor

[FeiZhuLulu]

Related Issue

Related to #1174

Problem

The prompt editor currently relies on keyboard navigation for cursor placement and text editing. Editing longer multi-line prompts is slow, while enabling terminal mouse reporting can interfere with native terminal selection unless the feature is explicitly gated and restores terminal state reliably.

What changed

Add experimental mouse text selection to the main prompt editor, enabled with KIMI_CODE_EXPERIMENTAL_TERMINAL_MOUSE_INPUT=1.

The editor now supports click-to-position, forward and reverse drag selection, wrapped and multi-line ranges, grapheme-safe deletion and replacement, atomic undo, and selected-text retrieval. Ctrl+C copies an active selection while preserving the existing cancel/exit behavior when no selection exists.

Kimi Code handles SGR mouse input only while the main editor is mounted, coalesces high-frequency drag events, maps coordinates from the latest rendered layout and actual viewport, and disables mouse reporting around dialogs, external editing, reloads, normal exit, and emergency terminal restoration. Holding Shift keeps terminal-native selection and scrollback behavior available.

English and Chinese documentation, package changesets, and regression coverage are included.

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue, or explained the problem above.
• I have added tests that prove my feature works.
• Ran gen-changesets skill, or this PR needs no changeset.
• Updated the English and Chinese docs; the gen-docs skill is not present in this checkout.

Verification

• pnpm --filter @moonshot-ai/pi-tui typecheck
• pnpm --filter @moonshot-ai/pi-tui exec node --test test/editor.test.ts test/tui-render.test.ts — 254 passed
• pnpm --filter @moonshot-ai/kimi-code typecheck
• pnpm --filter @moonshot-ai/kimi-code exec vitest run test/tui/editor-mouse.test.ts test/tui/components/editor/custom-editor.test.ts test/tui/controllers/editor-keyboard.test.ts test/tui/commands/reload.test.ts test/tui/kimi-tui-startup.test.ts test/utils/terminal-restore.test.ts — 131 passed
• pnpm exec vitest run packages/node-sdk/test/config.test.ts — 12 passed
• pnpm --filter @moonshot-ai/pi-tui build
• pnpm --filter @moonshot-ai/kimi-code build
• pnpm exec changeset status --since=origin/main
• git diff origin/main...HEAD --check
• Staged diff audit found no local paths, account identifiers, or credentials.
• Manual Windows Terminal validation covered repeated drag/delete cycles, wrapped multi-line text, CJK and ZWJ emoji, selection copy with Ctrl+C, lifecycle restoration, and coordinate stability after prompt shrinkage.

[changeset-bot]

🦋 Changeset detected

Latest commit: 4ff4f1f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@moonshot-ai/pi-tui	Minor
@moonshot-ai/kimi-code	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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