feat: Enhance chat prompt construction with prior findings and new ch…

[AnkanSaha]

…anges diff

• Updated constructChatPromptText to prefer priorFindings over full diff for efficiency.
• Added handling for newChangesDiff to ensure fresh commits are considered.
• Improved context sections in the prompt for better clarity.

feat: Introduce file review prompt for individual file analysis

• Created constructFileReviewPromptText to handle per-file reviews in a structured manner.
• Included context about the file, author, and related local context for better analysis.

feat: Implement merge review prompt for synthesizing findings

• Added constructMergeReviewPromptText to aggregate per-file results into a final review.
• Ensured the output adheres to a consistent JSON structure for downstream processing.

refactor: Centralize tone instructions for consistent feedback

• Created getToneInstructions to standardize tone and language guidance across prompts.
• Removed redundant tone instructions from individual prompts.

feat: Add concurrency utility for managing adapter requests

• Implemented mapWithConcurrency to limit concurrent requests and prevent rate-limiting issues.

feat: Introduce context budget management for diff character limits

• Replaced fixed character limits with a dynamic budget based on model context windows.
• Added functions to estimate tokens and fit findings to budget constraints.

feat: Implement local git context helpers for diff and file management

• Created functions to fetch local diffs, check reviewable files, and build a repo map.
• Added support for extracting signatures from files to enhance context during reviews.

test: Add comprehensive tests for concurrency, context budget, and git context utilities

• Implemented tests for mapWithConcurrency, contextBudget, and gitContext functionalities.
• Ensured coverage for edge cases and expected behaviors in various scenarios.