epic(flathub): get com.queryahub.querya_desktop accepted on Flathub #1583

Tracks the review of flathub/flathub#10606 (state: awaiting-review, test build failing at the manifest linter). Related: #1060.

Reviewer feedback (barthalion, 2026-10-14) and linter

• flathub: build from source instead of the prebuilt release zip #1578 build from source
• flathub: move to the latest GNOME runtime (48 is end-of-life) #1579 latest runtime
• flathub: sandbox permissions (home access and secrets) via portals #1580 permissions (home, secrets)
• flathub: ship desktop file, metainfo and icon from this repository #1581 upstream desktop/metainfo/icon
• flathub: answer the AI-disclosure question and keep the submission within the policy #1582 AI disclosure (teamcons)

Also in the submission checklist

• A video of the app running from the Flatpak (the template asks for it; the PR currently links a release page)
• Domain verification: https://queryahub.com/.well-known/org.flathub.VerifiedApps.txt (see QueryaHub/frontend)
• Meaningful development history and ongoing maintenance are stated in the PR
• flatpak-builder-lint clean for manifest and repo
• Comment bot, build after every fix; do not close the PR or merge master into it
• After approval: 2FA on the account that gets write access, accept the invitation within a week, set up the update flow (new tag to Flathub release)