* feat(share): export local usage cards with native KDE actions

Add a frozen aggregate usage preview, native image and text clipboard actions, and a local PNG save picker. Preserve unknown amounts, separate currencies, privacy, and capture cancellation; include a small repository attribution.

Documentation impact: update usage, requirements, development ownership, translations, the indexed synthetic screenshot, changelog, and TODO completed behavior. Verified with make check (local pyflakes unavailable), targeted export tests, two Plasma smoke layouts, packaging, and local installation.

* fix(share): rank models by tokens before display truncation