screenshots: sweep remaining committed-manifest wording

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/tools/screenshots/README.md

@@ -75,7 +75,7 @@ manifest atomically (with provenance: which run/branch/user), and snapshots the
 previous manifest for revert.
 
 ## Activation checklist
-- [x] `screenshot-manifest.json` generated ({name, engine} authoritative — derived from the per-engine baseline tree).
+- [x] Baseline manifest migrated to R2 (`baselines/pcbjam/manifest.json`, {name, engine} authoritative — written by morelli).
 - [x] `scale:'device'`→`'css'` normalized (no-op at CI's DSF=1).
 1. Add the `DISCORD_WEBHOOK_URL` repo secret — until then everything is inert.
 2. Calibrate: run the suite twice in CI, `screenshots:noise` the two dirs, set `FLOORS` in `config.ts`.

tests/tools/screenshots/r2-store.ts

@@ -2,11 +2,11 @@
  * Minimal S3 client for the content-addressed screenshot-baseline bucket.
  *
  * Baselines live in a PRIVATE R2 bucket as immutable objects keyed by content
- * hash (`sha256/<hex>.png`); the committed manifest (screenshot-manifest.json)
- * maps `<engine>/<name>` to a hash, so any git commit resolves its exact
- * baselines. Auth is a bucket-scoped S3 keypair — read-only in CI, read-write
- * for devs (promote) — via the env vars in config.ts R2_ENV; see this
- * directory's README for where to get credentials.
+ * hash (`sha256/<hex>.png`); the R2-hosted manifest
+ * (baselines/pcbjam/manifest.json, written only by the morelli app) maps
+ * `<engine>/<name>` to a hash. Auth is a bucket-scoped S3 keypair — read-only
+ * for fetch, a separate write pair for CI's run uploads — via the env vars in
+ * config.ts R2_ENV; see this directory's README for where to get credentials.
  *
  * aws4fetch does the SigV4 signing (dependency-free; region is always "auto"
  * on R2). Objects are never deleted here — a baseline prune only edits the