End-to-end tests for the full multi-file workflow: open 3 files, switch
buffers, cross-file symbols, import graph, project diagnostics, search,
rename across files, and batch query verification. 8/8 tests passing.
Sprint 9 complete: 212/212 tests across all 4 phases (Steps 245-262).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
