Priority 3: Fix Integration Test Failures - COMPLETE

Status: Success

Fixed all 4 integration test failures with 3 targeted fixes:
1. Trailing comma parsing in Rust match preprocessor (1 fix, 3 lines)
2. Missing ctx.CurrentFile in integration tests (4 fixes, 1 line each)
3. Missing panic statement after exhaustive matches (1 fix, 11 lines)

Tests: 4/4 passing (pattern_match_rust_syntax, pattern_match_non_exhaustive_error, none_context_inference_return, combined_pattern_match_and_none)

Files Modified:
- pkg/preprocessor/rust_match.go (2 changes)
- tests/integration_phase4_test.go (4 changes)

Details: ai-docs/sessions/20251119-142658/02-implementation/task-priority3-changes.md
Notes: ai-docs/sessions/20251119-142658/02-implementation/task-priority3-notes.md
