restrict tools to scope for cost savings on large repo

[khezen]

this PR aims to reduce costs on large repo by restricting MCP servers to the sub scope being reviewed.

[khezen]

🔍 CodeSpy Review

Issues Found: 0 | Critical: 0 | High: 0 | Medium: 0

📋 Summary

Restricts MCP filesystem/parser tools to scope subroot directories instead of the full repository root, reducing token consumption and cost on large monorepos. Adds helper functions for path translation between repo-relative and scope-relative coordinates, and restructures both reviewers to create/destroy tool contexts per-scope rather than once globally.

🎯 Quality Assessment

Well-structured. Clean separation of concerns: path utilities extracted to helpers, scope-restriction logic consistent across both reviewer modules. Proper resource cleanup with per-scope finally blocks. Edge cases handled ("." subroot passthrough). OSV tools correctly shared since they have no filesystem dependency. The categories input field addition is a good decoupling.

📊 Statistics

Metric	Count
Total Issues	0
Critical	0
High	0
Medium	0
Low	0
Security	0
Bugs	0
Documentation	0

💰 Cost Summary

Total: $0.9618 | Tokens: 125,791 | LLM Calls: 11

Signature	Cost	Tokens	Calls	Duration
code_and_doc_review	$0.7416	70,559	3	229.7s
scope_identification	$0.1560	45,585	7	67.1s
summarization	$0.0642	9,647	1	18.0s

💡 Recommendation

APPROVE — Correct implementation of scope-restricted tooling. No defects found. Pattern is consistent across both modules, path handling covers edge cases, and resource cleanup is properly scoped.