Phase 1 (miroir-cdo): Add coverage verification to DoD

- Added cargo-llvm-cov coverage report to notes
- Phase 1 core modules all exceed 90% line coverage:
  - router.rs: 96.76%
  - topology.rs: 100.00%
  - merger.rs: 95.45%
- All 82 tests pass
- All DoD criteria verified

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

notes/miroir-cdo.md

@@ -41,6 +41,7 @@ Phase 1 Core Routing implementation is complete and verified. All Definition of
 - [x] `covering_set` within a group returns exactly one node per shard (verified by `test_covering_set_one_per_shard`)
 - [x] `merger` passes the merge/facet/limit tests (15 merger tests all pass)
 - [x] 82/82 tests pass in miroir-core
+- [x] Phase 1 modules ≥ 90% line coverage via cargo-llvm-cov
 
 ## Test Results
 
@@ -50,8 +51,19 @@ test result: ok. 82 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
 
 All router, topology, and merger tests pass successfully.
 
+## Coverage Report (Phase 1 Core Modules)
+
+```
+router.rs:    96.76% line coverage (674 regions, 15 missed)
+topology.rs: 100.00% line coverage (251 regions, 0 missed)
+merger.rs:    95.45% line coverage (641 regions, 7 missed)
+```
+
+All Phase 1 core modules exceed the 90% coverage requirement.
+
 ## Notes
 
 - Hash seed changed from 0 to 42 to improve distribution properties for the 64/3/RF=1 test case
 - All three properties of rendezvous hashing (determinism, minimal reshuffling, group isolation) are verified
 - Implementation follows plan §2 Architecture + §4 router.rs specifications
+- scatter.rs is stubbed (full execution wired in Phase 2)