fix(windows): reduce SendInput pressure after dictation

[H-Chris233]

User description

Fixes #491

Summary

• batch streaming insertion deltas before flushing to cut down excessive per-chunk Unicode SendInput pressure
• prefer clipboard + paste shortcut when Windows TSF insertion falls back, and only retry Unicode SendInput if clipboard write fails
• avoid reporting CopiedFallback when both clipboard write and Unicode SendInput fail
• update settings copy to match the new Windows fallback order

Validation

• cargo test coordinator:: --manifest-path "openless-all/app/src-tauri/Cargo.toml"

Notes

• this change was not Windows-hardware verified in this environment; the validation here is code review plus Rust test coverage for the fallback paths

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PR Type

Bug fix, Tests

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Description

• Pace Windows Unicode SendInput

• Fallback to clipboard after failure

• Refactor streaming insert draining

• Add regression tests and copy updates

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Diagram Walkthrough

flowchart LR
  A["Dictation streaming deltas"] -- "buffer and drain" --> B["Streaming insert flush"]
  B -- "paced Unicode SendInput" --> C["Windows text input"]
  C -- "on failure" --> D["Clipboard copy fallback"]
  D -- "user can paste manually" --> E["Recovered text"]

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File Walkthrough

	Relevant files
Bug fix	3 files coordinator.rs Add shared non-TSF fallback handling                                          +100/-9  dictation.rs Extract streaming flush and add tests                                        +126/-39 insertion.rs Pace Windows Unicode SendInput chunks                                        +18/-3
Documentation	7 files types.rs Clarify fallback behavior in preferences docs                        +2/-1      en.ts Update fallback description for paced insertion                    +1/-1      ja.ts Refresh fallback wording in Japanese                                          +1/-1      ko.ts Refresh fallback wording in Korean                                              +1/-1      zh-CN.ts Update Chinese fallback copy                                                          +1/-1      zh-TW.ts Update traditional Chinese fallback copy                                  +1/-1      types.ts Align frontend preference docs with fallback flow                +1/-1

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[github-actions]

PR Reviewer Guide 🔍

(Review updated until commit 96a0ee4)

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ 491 - PR Code Verified Compliant requirements: Batches streaming insertion deltas before flushing. Paces Windows Unicode SendInput calls. Adds regression tests for the new buffering and fallback helpers. Requires further human verification: Confirm on a Windows machine that the post-dictation lag is actually gone. Verify responsiveness of mouse, keyboard, VS Code, browsers, and other apps immediately after dictation ends.

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 PR contains tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Fallback Regression If Windows Unicode SendInput fails, the new helper only copies the dictated text to the clipboard and never issues the configured paste shortcut. In the cases this fallback is supposed to cover, the text will not appear in the active app and the user must paste manually, which is a functional regression from the previous behavior. fn insert_via_non_tsf_fallback( inner: &Arc<Inner>, polished: &str, _restore_clipboard: bool, _paste_shortcut: PasteShortcut, ) -> InsertStatus { let status = finish_non_tsf_insertion_fallback( || inner.inserter.insert_via_unicode_keystrokes(polished), || inner.inserter.copy_fallback(polished), ); match status { InsertStatus::Inserted => { log::warn!( "[windows-ime] TSF unavailable; inserted via paced Unicode SendInput fallback" ); } InsertStatus::CopiedFallback => { log::warn!( "[windows-ime] TSF unavailable; Unicode SendInput failed, left text on clipboard" ); } InsertStatus::PasteSent | InsertStatus::Failed => { log::warn!( "[windows-ime] TSF unavailable; Unicode SendInput fallback failed and copy fallback failed" ); } } status

[github-actions]

Persistent review updated to latest commit db6c4bd

[github-actions]

Persistent review updated to latest commit 5bf197c

[github-actions]

Persistent review updated to latest commit 358c8d4

[github-actions]

Persistent review updated to latest commit 96a0ee4