Keyboard Manager Text Injection Broken - Service Crashes, Key Repeat Flood, Full Keyboard Lockup

### Microsoft PowerToys version
0.99.1
### Installation method
Microsoft Store
### Area(s) with issue?
Keyboard Manager
### Steps to reproduce
Keyboard Manager text injection shortcuts are completely non-functional and actively dangerous to system stability. Issue predates the latest update and was not resolved by updating to v0.99.1.

**Steps to reproduce:**
1. Create a text injection shortcut in Keyboard Manager with a long string
2. Trigger the shortcut in any application
3. Observe garbled/partial output with repeated characters flooding the input field
4. Keyboard enters a broken state where individual characters repeat uncontrollably (e.g. "nnnnnnn", "uuuuuuu")
5. After garbled output, the shortcut stops firing entirely and no further text injection is possible until Keyboard Manager is toggled off/on or PowerToys is restarted.

**Actual behavior:**
- Keyboard Manager service drops after firing ("Keyboard Manager service is down")
- Text injection works once or twice initially, then stops functioning entirely
- When it does fire, output is garbled with repeated characters flooding the input field
- Shortcut stops firing until Keyboard Manager is toggled or PowerToys is restarted
- Toggling to restore functionality can trigger additional garbled output

**Additional context:**
- Previously worked reliably on prior versions
- Related to closed issue #26840 from 2023 - appears to have regressed
- Tested on Windows 11 Pro 64-bit Build 26200, MSI i5-12600K, 32GB RAM

### Expected Behavior
Text string is injected cleanly into the active input field without errors or keyboard state corruption.

### Actual Behavior
- Keyboard Manager service drops after firing ("Keyboard Manager service is down")
- Text injection works once or twice initially, then stops functioning entirely
- When it does fire, output is garbled with repeated characters flooding the input field
- Shortcut stops firing until Keyboard Manager is toggled or PowerToys is restarted
- Toggling to restore functionality can trigger additional garbled output

### Upload Bug Report ZIP-file
_No response_

### Additional Information
OS version: Windows 11 Pro 64-bit Build 26200
System Language: English
User or System Installation: User
Running as admin: No

**Troubleshooting attempted:**
- Issue was present before updating to v0.99.1
- Updated PowerToys to v0.99.1 - issue persisted
- Toggled Keyboard Manager off/on - triggered garbled injection and worsened lockup
- Switched to new editor and back to classic editor - no improvement
- Full system reboot - issue persisted
- Ctrl+Alt+Del required to recover keyboard after lockup
- Non-text key remapping shortcuts appear unaffected throughout

**Additional observations:**
- Keyboard Manager service drops within seconds of PowerToys launch, even without triggering any shortcut
- Issue is not shortcut-specific - tested with multiple different key combinations, same result
- Classic editor vs new editor makes no difference - service crashes regardless
- Duplicate shortcut with different key combination also fails identically

### Other Software
NA - Brave Browser, AWS Workspace, General Apps... Never an issue prior.

**Screenshot showing "Keyboard Manager service is down" error in the new editor after text injection fires once and stops responding:**

Start by reproducing the failure through Keyboard Manager text injection with a long string and observe the service-down, repeated-key, and lockup behavior described here. Compare text injection with unaffected non-text remapping and verify that completion means clean, repeatable injection without a service crash or keyboard-state corruption.

Written by the indexing model from the issue text.