[WIP] Symbol properties on objects are imported by type and not by value when auto-completed

[Copilot]

• [x] Analyze the issue: Symbol properties on objects are imported by type instead of value when auto-completed
• [x] Explore repository structure and build system
• [x] Create a fourslash test to reproduce the bug
• [x] Run the test to verify it fails
• [x] Identify the root cause in the language service
• [x] Fix the bug
• [ ] Verify the fix works
• [ ] Run all tests to ensure no regressions
• [ ] Format and lint code

Root Cause: When there's an existing type-only import, the auto-import system incorrectly adds value imports to it instead of creating mixed imports or separate imports.

Fix: Modified tryAddToExistingImport in importFixes.ts to:

1. Only return perfect matches for type-only requirements (Required+TypeOnly or NotAllowed+Value)
2. Skip incompatible combinations (value imports going to type-only imports)
3. Handle cases where addAsTypeOnly is Allowed but should prefer value imports

Testing: Verified that completely disabling existing import addition fixes the issue (creates separate imports). The targeted fix is in the right location but may need refinement.

Test Case: Simple case that reproduces the issue:

import type { SomeType } from "./exports";  // existing type-only
VALUE;  // auto-complete this → should create mixed/separate import

Fixes #61894.

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