v1.6.3

Test Coverage Improvements

CI: Enable Tier 2/3 E2E tests

Tier 2 (component injection, content validation, idempotency — ~78 tests) and Tier 3 (backup/restore — 6 tests) E2E tests now run in CI. Previously only Tier 1 (flags/dry-run — 27 tests) executed, meaning injection regressions could ship undetected.

New: Dry-run parity integration test

Verifies that files listed in --dry-run output actually get created during real install. Catches drift between planning and execution.

New: Upgrade idempotency integration test

Runs install twice with the same flags and asserts byte-level idempotency — no duplicate orchestrator sections, no duplicate MCP entries, no duplicate markers.

New: Golden tests for Cursor, Gemini CLI, and VSCode

These 3 agents (out of 5 supported) previously had zero integration test coverage for SDD injection. Now each has golden file tests verifying correct config paths and content.

+1,343 lines of test code across 9 files.