docs: comprehensive Sourcegraph baseline vs MCP analysis report

Detailed analysis of 6 Sourcegraph monorepo tasks comparing baseline
(full local source) vs MCP (sg_only truncated source + Sourcegraph tools).
Includes environment setup, task instructions, tool call traces, verifier
results, and recommendations for improving MCP configuration.

Key finding: after fixing two baseline Dockerfile bugs, baseline outperforms
MCP by 0.057 mean score (0.827 vs 0.770). MCP wins on 1/6 tasks (precision-
focused audit), loses on 3/6, ties on 2/6.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sjarmak