feat(amazonq): add experiment for basic e2e flow of inline chat through Flare. (#7235)

## Problem
This is the initial set of work required to get inline chat running
through flare.

## Solution
- **add a feature flag for inline chat**: this allows testing of the two
implementations side-by-side by flipping the feature flag.
- **move general utils out of chat**: stuff like encryption and
editorState can all be reused.
- **render full diff response from inline chat**: this does not include
progress updates from the language server.

## Testing and Verification


https://github.com/user-attachments/assets/0dff58b7-40f7-487d-9f9e-d58610201041



## Future Work / Next Steps
- ensure telemetry is still being emitted. 
- add tests for new flow. (there aren't any for the existing one)
- handle partial events from the language server. 

## Known Bugs
- selecting part of a line will cause the text to insert mid-line 
- running inline-chat without a selection causes the entire file to be
copied (This is in JB, Eclipse Prod, but IMO it makes the feature
unusable).


---

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Author: Hweinstock