The spend page links to /fleet/graph carrying its filter #11057

Replaces the open box of #578. The board and the app page already link to the graph.

Done when:

• [ ] src/web/pages/spend.ts renders a plain <a href="/fleet/graph?q=…">, with the page's current filter URL-encoded and escaped as the graph's q. With no filter it is plain /fleet/graph.
• [ ] A test asserts the link with and without a filter, including a filter holding & and <.

Files: src/web/pages/spend.ts, its test Suits: scout

Done on main already, waiting for you to close it: 33131c3a5308e1966f9e3d8824b91c4c518496aa

Closed: already done on main in 33131c3. Closed by the crew's live triage; reopen it to undo, and it stays open.