docs: polish digest output workflow rules

reader-digest-flow/references/flow.md

@@ -85,7 +85,15 @@ Recommended generation pattern:
 - Ask the model to return both outputs in one response.
 - Prefer a structured response shape (for example JSON with `public_digest_markdown` and `internal_review_digest_markdown`) when post-processing is needed.
 
-Write only the public digest into Hugo here:
+Before publishing, persist the generated digest artifacts back into the same reader run directory:
+
+```text
+outputs/freshrss/rerun/<run-id>/digest/public_digest.md
+outputs/freshrss/rerun/<run-id>/digest/internal_review_digest.md
+outputs/freshrss/rerun/<run-id>/digest/combined.json
+```
+
+Then write only the public digest into Hugo here:
 
 ```text
 /home/ubuntu/zhu/apps/hugo-site/content/daily/YYYY-MM-DD/index.md
@@ -107,7 +115,6 @@ Recommended **public digest** structure:
 - `今日重点`
 - `趋势观察`
 - `延伸阅读`
-- `信息来源`
 
 Public digest constraints:
 
@@ -115,6 +122,7 @@ Public digest constraints:
 - Keep public wording free of internal workflow language.
 - Optimize for concise public readability with solid information density.
 - For each `今日重点` item, add one short editor-style sentence explaining why the item matters in today's digest (for example: `这篇内容更值得关注的原因在于……`).
+- Prefer rendering highlight points as a short public label such as `值得关注：` followed by one bullet per line.
 
 Recommended **internal review digest** structure: