[psxjoy]

Purpose of the pull request

Document the security model of Apache Fesod (Incubating) so users understand its trust boundaries, security guarantees, and application and deployment responsibilities.

What's changed?

• Add English and Chinese Security Model pages covering temporary files, caches, password protection, untrusted documents, resource isolation, and file and network access.
• Explain the dependency on Apache POI, including its limitations and the intention to preserve its security model, API contracts, and protective checks.
• Clarify that XLSX output encryption does not imply encryption of intermediate files or JVM memory, and that temporary-file access and heap access are separate permissions.
• Add community navigation and links from the existing Security and Password Protection pages.
• Standardize project references as Apache Fesod (Incubating).

Validation includes Markdown linting, English and Chinese production builds, and checks of generated navigation links and section anchors using the existing local dependencies. No Java runtime behavior is changed.

Checklist

• I have read the [Contributor Guide](https://fesod.apache.org/community/contribution/).
• I have written the necessary doc or comment.
• No unit tests are required for this documentation-only change.

[bengbengbalabalabeng]

I noticed that only some of the H2 headings explicitly define custom anchor IDs (such as {#apache-poi}), while the other sections do not.

Just wondering, is this intentional for specific deep-linking/referencing needs, or would it be better to standardize the format across the entire document?

[psxjoy]

Thanks @bengbengbalabalabeng. These explicit IDs serve the cross-page links from the English and Chinese Password Protection pages: #apache-poi, #temporary-files-and-caches, and #password-protection.

Keeping the same IDs in both languages makes those links stable when headings are translated or reworded. The remaining sections use Docusaurus-generated IDs, which still support navigation and linking. I've kept the existing anchors unchanged because only these three sections currently need shared, stable targets for those references.