flathub: answer the AI-disclosure question and keep the submission within the policy #1582

Part of #1060. A reviewer quoted our checked box "I have disclosed any AI-generated material..." and asked where the disclosure is (flathub/flathub#10606).

Policy (Generative AI policy):

• submitters "must disclose any AI-generated code, documentation, packaging, or other material" included in the app or its packaging
• "Flathub manifests must not contain AI-generated or AI-assisted content" (disclosure does not exempt them)
• "AI tools or agents must not open or automate Flathub submission pull requests", and AI-agent reviews must not be requested
• AI used only for research, discussion or debugging needs no disclosure when nothing generated is included
• undisclosed or misrepresented material can mean rejection; repeated violations a permanent ban

Work

• The maintainer reviews the manifest, desktop/metainfo files and the PR text and answers the reviewer truthfully in the PR (what, if anything, was AI-assisted)
• Rewrite the manifest by hand if any of it was AI-generated or AI-assisted
• Correct the PR checkboxes if they do not reflect reality
• From now on: the submission PR and all replies to reviewers are written by a human
• Add a short note about AI-assisted parts of the app itself to the repo docs, if that applies