[Site]: Identical fallback description used across all Monthly Report blog summaries

### Current State

### Current State
On the Apache APISIX Blog main page (https://apisix.apache.org/blog/), all posts titled **"2026 Monthly Report (Month DD - Month DD)"** share the exact same fallback abstract/description text under the title.

**The repetitive text:**
> "Our monthly Apache APISIX community report generates insights into the project's monthly developments. The reports provide a pathway into the Apache APISIX community, ensuring that you stay well-informed and actively involved."

While this description accurately defines what a monthly report is, having identical snippets for multiple distinct posts on the main feed reduces readability and SEO efficiency. It prevents users from seeing unique highlights of that specific month (e.g., specific feature highlights or milestone metrics) without clicking into the article.

### Link to the page
https://apisix.apache.org/blog/

### Desired State

**Description of the change you are proposing**:

### Expected Behavior / Proposal
Each monthly report should ideally have a unique summary snippet on the blog feed that outlines that specific month's key updates or highlights (e.g., "In May, we introduced new authentication plugins for Feishu and DingTalk...").

Alternatively, if a template must be used, it should dynamically include the specific month or a brief subhead to distinguish one report from another on the list page.

### Would you like to fix this issue?

No. Please assign another contributor

Start at the Apache APISIX Blog main page and inspect the monthly report posts and the code or content that supplies their fallback descriptions. Determine whether each report can expose a distinct summary or whether the list-page template should distinguish reports by month. Done means the monthly report entries no longer display identical summaries on the blog feed.

Written by the indexing model from the issue text.