Fuzzy turbo edits (#1700)

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> Makes search-replace tolerant to typos/whitespace via two-pass fuzzy
matching with Levenshtein and smart-quote normalization, with clearer
errors and tests.
> 
> - **Search/Replace Processor
(`src/pro/main/ipc/processors/search_replace_processor.ts`)**
> - Add two-pass fuzzy matching: quick exact-line prefilter +
Levenshtein scoring (`fastest-levenshtein`).
> - Match flow: exact > whitespace-insensitive > fuzzy; detect ambiguity
and improve error messages with similarity %.
> - Introduce thresholds and limits: `FUZZY_MATCH_THRESHOLD=0.9`,
`EARLY_STOP_THRESHOLD=0.95`, `MAX_FUZZY_SEARCH_TIME_MS=10000`.
> - Normalize text before scoring using `normalizeString` (handles
quotes, dashes, ellipsis, NBSP, soft hyphen, BOM).
> - Preserve indentation for replacements; keep existing
unescape/validation logic.
> - **Utils (`src/utils/text_normalization.ts`)**
> - New `normalizeString` helper for Unicode normalization used by fuzzy
matching.
> - **Tests
(`src/pro/main/ipc/processors/search_replace_processor.test.ts`)**
> - Add cases for typos, smart quotes, below-threshold failure,
exact-over-fuzzy preference, whitespace differences, and ambiguity.
> - **Dependencies**
>   - Add `fastest-levenshtein` to `package.json`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
289dab915c37bc4f9ab4bf0209ff3f95a57341fc. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->



<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Makes applySearchReplace more tolerant by preferring exact and
whitespace-insensitive matches, then falling back to fast two-pass
Levenshtein-based fuzzy matching with Unicode normalization. Improves
failure messages and adds tests to cover common edit scenarios.

- **New Features**
- Exact > whitespace-insensitive > fuzzy matching flow (threshold 0.9).
- Two-pass fuzzy search with exact-line prefilter; early stop at 0.95
and 10s timeout.
- normalizeString handles smart quotes, dashes, ellipsis, NBSPs, soft
hyphen, and BOM.
  - Errors now report best fuzzy similarity when below threshold.
- Tests for typos, smart quotes, below-threshold cases,
exact-over-fuzzy, whitespace differences, and ambiguity.

- **Dependencies**
  - Add fastest-levenshtein.

<sup>Written for commit 289dab915c37bc4f9ab4bf0209ff3f95a57341fc.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->

package.json

@@ -138,6 +138,7 @@
     "electron-playwright-helpers": "^1.7.1",
     "electron-squirrel-startup": "^1.0.1",
     "esbuild-register": "^3.6.0",
+    "fastest-levenshtein": "^1.0.16",
     "fix-path": "^4.0.0",
     "framer-motion": "^12.6.3",
     "geist": "^1.3.1",