openspec: fix quality review issues in performance-teaching-hardening

- Resolve vectorization flag inconsistency: use -fopt-info-vec-optimized
  consistently across design.md, tasks.md, and simd-vectorization/spec.md,
  matching the existing docs/en/guides/learning-path.md content

- Resolve dispatch_example ambiguity: add dispatch_example_main.cpp and
  dispatch_example executable target explicitly to the file surface table
  and tasks (was referenced in the Mermaid diagram but undefined elsewhere)

- Remove prose hedging in design.md: replace 'Add a page (or expand an
  existing section)' with the concrete docs/en/guides/validation.md path
  that was already decided in the file surface table

- Make SIMD test path concrete: tests/unit/simd/simd_dispatch_test.cpp
  (matching the existing tests/unit/simd/ layout); add note about compiling
  without -mavx2 to exercise the runtime guard

- Clarify ci-quality-assurance tombstone: add comment block explaining the
  intentional omission so implementers do not question the empty delta

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: LessUp

openspec/changes/performance-teaching-hardening/design.md

@@ -39,15 +39,17 @@ graph TD
 
 **Goal**: Make compiler vectorization reports reachable without reading CMakeLists.txt.
 
-**Approach**: Add a "Vectorization Diagnostics" section to `examples/04-simd-vectorization/README.md` that shows the exact build commands (`cmake --preset=debug -DCMAKE_CXX_FLAGS="-fopt-info-vec"` / `-Rpass=loop-vectorize`) and how to read the output. Mirror a condensed version in `docs/` under the SIMD learning path entry.
+**Approach**: Add a "Vectorization Diagnostics" section to `examples/04-simd-vectorization/README.md` that shows the exact build commands (`cmake --preset=debug -DCMAKE_CXX_FLAGS="-fopt-info-vec-optimized"` / `-Rpass=loop-vectorize`) and how to read the output. Mirror a condensed version in `docs/` under the SIMD learning path entry.
+
+**Flag note**: Use `-fopt-info-vec-optimized` (not the broader `-fopt-info-vec`) for GCC because it reports only successfully vectorized loops, which is more useful for teaching. The existing `docs/en/guides/learning-path.md` already uses `-fopt-info-vec-optimized`; this change must stay consistent with that.
 
 **Trade-off**: We do not add a new CMake preset for this; a reader-visible flag override is sufficient and avoids preset sprawl.
 
 ### 3. Sanitizer workflow in reader-facing docs
 
 **Goal**: A reader can find and run ASan/TSan/UBSan without knowing the preset names in advance.
 
-**Approach**: Add a "Validation and Safety" page (or expand an existing section) in the VitePress docs site. Reference the three preset names (`asan`, `tsan`, `ubsan`) with copy-pasteable commands. Cross-link from the repository README quick-start.
+**Approach**: Add `docs/en/guides/validation.md` as a new VitePress page in the docs site. Reference the three preset names (`asan`, `tsan`, `ubsan`) with copy-pasteable commands. Cross-link from the repository README quick-start.
 
 **Trade-off**: Keep this as documentation only. Do not add a new composite preset or script; the existing presets are complete.
 
@@ -65,9 +67,10 @@ graph TD
 
 | Path | Change |
 |------|--------|
-| `examples/04-simd-vectorization/src/runtime_dispatch.cpp` | New: runtime CPU dispatch example |
-| `examples/04-simd-vectorization/CMakeLists.txt` | Extend: add `simd_dispatch` STATIC library target |
-| `tests/` (simd subdir) | New: correctness test for `dispatch_add_arrays` |
+| `examples/04-simd-vectorization/src/runtime_dispatch.cpp` | New: runtime CPU dispatch implementation |
+| `examples/04-simd-vectorization/src/dispatch_example_main.cpp` | New: `dispatch_example` executable entry point |
+| `examples/04-simd-vectorization/CMakeLists.txt` | Extend: add `simd_dispatch` STATIC library target and `dispatch_example` executable target |
+| `tests/unit/simd/simd_dispatch_test.cpp` | New: correctness test for `dispatch_add_arrays` |
 | `examples/04-simd-vectorization/README.md` | Extend: vectorization diagnostics section |
 | `docs/en/guides/learning-path.md` | Extend: vectorization diagnostics, sanitizer cross-link |
 | `docs/en/guides/validation.md` | New: sanitizer preset workflow (asan/tsan/ubsan) |

openspec/changes/performance-teaching-hardening/specs/ci-quality-assurance/spec.md

@@ -1,3 +1,7 @@
 # CI and Quality Assurance
 
+<!-- Intentional delta: no new requirements are added to this capability in this change. -->
+<!-- This file exists to confirm the omission was deliberate. The benchmark regression -->
+<!-- script smoke-test requirement is owned by the `benchmark-framework` capability. -->
+
 No new requirements added in this change. The benchmark regression script smoke-test requirement is owned by the `benchmark-framework` capability.

openspec/changes/performance-teaching-hardening/specs/simd-vectorization/spec.md

@@ -24,5 +24,5 @@ THE Documentation SHALL document how to obtain compiler vectorization reports fo
 
 #### Scenario: Reader enables vectorization diagnostics
 
-- **WHEN** a reader builds the SIMD examples with GCC (`-fopt-info-vec`) or Clang (`-Rpass=loop-vectorize`)
+- **WHEN** a reader builds the SIMD examples with GCC (`-fopt-info-vec-optimized`) or Clang (`-Rpass=loop-vectorize`)
 - **THEN** the module README provides the exact command and an explanation of the output

openspec/changes/performance-teaching-hardening/tasks.md

@@ -4,13 +4,14 @@
 
 - [ ] 1.1 Add `examples/04-simd-vectorization/src/runtime_dispatch.cpp` with `hpc::simd::dispatch_add_arrays` using `__builtin_cpu_supports` for AVX2/SSE2/scalar selection
 - [ ] 1.2 Add a `simd_dispatch` STATIC library target in `examples/04-simd-vectorization/CMakeLists.txt` (separate from the INTERFACE `simd_utils` target) that compiles `runtime_dispatch.cpp` and links `simd_utils` for headers
-- [ ] 1.3 Add a correctness test under `tests/` that calls `dispatch_add_arrays` and validates results against the scalar reference
-- [ ] 1.4 Verify `cmake --preset=debug && cmake --build build/debug && ctest --preset=debug` passes with the new target and test
+- [ ] 1.3 Add `examples/04-simd-vectorization/src/dispatch_example_main.cpp` and a `dispatch_example` executable target in `examples/04-simd-vectorization/CMakeLists.txt` that links `simd_dispatch` and demonstrates runtime dispatch
+- [ ] 1.4 Add `tests/unit/simd/simd_dispatch_test.cpp` (and wire it into `tests/unit/simd/CMakeLists.txt`) that calls `dispatch_add_arrays` and validates results against the scalar reference; note: the test must compile without `-mavx2` so the runtime guard is exercised on machines without AVX2
+- [ ] 1.5 Verify `cmake --preset=debug && cmake --build build/debug && ctest --preset=debug` passes with the new targets and test
 
 ## 2. Vectorization diagnostics documentation
 
-- [ ] 2.1 Add a "Vectorization Diagnostics" section to `examples/04-simd-vectorization/README.md` with GCC (`-fopt-info-vec`) and Clang (`-Rpass=loop-vectorize`) flag examples and sample output
-- [ ] 2.2 Extend `docs/en/guides/learning-path.md` (SIMD section) to surface the vectorization diagnostics workflow for readers
+- [ ] 2.1 Add a "Vectorization Diagnostics" section to `examples/04-simd-vectorization/README.md` with GCC (`-fopt-info-vec-optimized`) and Clang (`-Rpass=loop-vectorize`) flag examples and sample output
+- [ ] 2.2 Extend `docs/en/guides/learning-path.md` (SIMD section) to surface the vectorization diagnostics workflow for readers, using `-fopt-info-vec-optimized` to stay consistent with the existing content in that file
 
 ## 3. Sanitizer workflow documentation