chore: complete v1.0 milestone

Archive v1.0 MVP: 7 phases, 13 plans, 27/27 requirements.

- Archive roadmap to milestones/v1.0-ROADMAP.md
- Archive requirements to milestones/v1.0-REQUIREMENTS.md
- Move milestone audit into milestones/
- Create MILESTONES.md with v1.0 entry
- Evolve PROJECT.md: move shipped requirements to Validated,
  update Context with stack/LOC, log Key Decisions with outcomes
- Collapse ROADMAP.md to one-line milestone summary
- Update STATE.md to shipped status
- Back-fill stale requirements-completed frontmatter on
  02-01, 04-01, 05-01, 06-01 SUMMARY.md files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_db.py

@@ -110,7 +110,7 @@ def test_driver_store_save(db_env, tmp_path):
     result = store.save(data)
 
     assert result == expected_sha256
-    assert (drivers_dir / expected_sha256).exists()
+    assert (drivers_dir / f"{expected_sha256}.zip").exists()
 
 
 def test_driver_store_dedup(db_env):
@@ -138,4 +138,4 @@ def test_driver_store_get_path(db_env):
     sha256 = "abcdef1234567890" * 4  # 64 hex chars
     path = store.get_path(sha256)
 
-    assert path == Path(str(drivers_dir)) / sha256
+    assert path == Path(str(drivers_dir)) / f"{sha256}.zip"