fix(#1264): preserve portable standalone launch

docs/reports/code-review/1264-code-review.md

@@ -71,6 +71,25 @@ Result: risk `none`, confidence `0.93`, 9 files, no critical/high/medium/low fin
 could not run Vitest because Vite attempted to create a temporary config artifact on its read-only
 mount (`EROFS`); executor-owned focused and full results are recorded in the QA report.
 
+## Second exact-head review
+
+Daphne reviewed exact head `9dc90be7e13b1cd609f6df97d43d890ef5392ca0` and filed Gitea review
+ID 169 as `REQUEST_CHANGES`. Review 169 confirmed all review-168 closures, then found:
+
+1. the new point-of-use reader was Linux-only but had been applied to every standalone USER read,
+   breaking supported non-fleet macOS composition; and
+2. explicit blank/whitespace `MOSAIC_AGENT_CLASS` was treated as absent and could seed before
+   runtime, while only undefined should mean absent.
+
+Red-first remediation preserves legacy `readOptional()` for standalone composition, keeps descriptor
+no-follow consumption fleet-only, moves the replacement-symlink case under a valid fleet identity,
+and rejects defined blank/whitespace classes before seeding. Three blank-class CLI cases and one
+tolerant standalone composition case failed before the source change and pass after it.
+
+Review-169 remediation code review approved at confidence `0.90` (4 files, no findings). Security
+review reported risk `none` at confidence `0.90` (4 files, no findings). The review sandbox retained
+its known Vite `EROFS` limitation; executor-owned tests are in the QA report.
+
 ## Remaining review gate
 
 Daphne must re-review the next exact pushed head. This report cannot record that future verdict