Fixes #1222 #1646 

TODOs
- [x] description?
- [x] collect errors across all files for turbo edits
- [x] be forgiving around whitespaces
- [x] write e2e tests
- [x] do more manual testing across different models



<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds Turbo Edits v2 search-replace flow with settings/UI selector,
parser/renderer, dry-run validation + fallback, proposal integration,
and comprehensive tests; updates licensing.
> 
> - **Engine/Processing**:
> - Add `dyad-search-replace` end-to-end: parsing
(`getDyadSearchReplaceTags`), markdown rendering (`DyadSearchReplace`),
and application (`applySearchReplace`) with dry-run validation and
fallback to `dyad-write`.
> - Inject Turbo Edits v2 system prompt; toggle via
`isTurboEditsV2Enabled`; disable classic lazy edits when v2 is on.
> - Include search-replace edits in proposals and full-response
processing.
> - **Settings/UI**:
> - Introduce `proLazyEditsMode` (`off`|`v1`|`v2`) and helper selectors;
update `ProModeSelector` with Turbo Edits and Smart Context selectors
(`data-testid`s).
> - **LLM/token flow**:
> - Construct system prompt conditionally; update token counting and
chat stream to validate and repair search-replace responses.
> - **Tests**:
> - Add unit tests for search-replace processor; e2e tests for Turbo
Edits v2 and options; fixtures and snapshots.
> - **Licensing/Docs**:
> - Add `src/pro/LICENSE` (FSL 1.1 ALv2 future), update root `LICENSE`
and README license section.
> - **Tooling**:
> - Update `.prettierignore`; enhance test helpers (selectors, path
normalization, snapshot filtering).
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
7aefa02bfae2fe22a25c7d87f3c4c326f820f1e6. This will update automatically
on new commits. Configure
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<!-- /CURSOR_SUMMARY -->