Add an OSM signup prompt to the reporting-method and app pages

[munzzyy]

Closes #86.

Both reporting methods write to OpenStreetMap, but the only "create an account" link on the site is buried in step 1 of the iD stepper on /report/id. Someone landing on /report or /app gets no hint they need an account until they hit the login wall. That's the gap the issue is pointing at.

Two changes:

• ReportChoose.vue — an info v-alert under the intro line, before the two method cards, saying both paths save to OSM and linking to openstreetmap.org/user/new.
• DeflockApp.vue — a line under the download CTA noting the same thing, since the issue asked about the app page too. That section sits on the purple gradient, so there's a small scoped rule making the link inherit white instead of rendering default-blue on purple.

Wording matches the existing link on /report/id. No new deps, no state, no telemetry.

Checked with npm run build-only (no bun here, and package-lock.json is in the repo so npm works) and rendered both pages against vite dev. npm run type-check does fail, but on App.vue and a @vitejs/plugin-vue type declaration. Both are already broken on master and neither is touched here.

[frillweeman]

Thanks! Chatting this over with @stopflock

[stopflock]

Thank you for this - had forgotten there was an issue open for it, but it came up again recently.

The new blurb on the app page is not as prominent, being at the bottom.
I'd also like to include a link to OSM's About page. Maybe something like this instead?:

Submitting or editing map data requires signing up for a free <a href="https://wiki.openstreetmap.org/wiki/About_OpenStreetMap">OpenStreetMap</a> account. You can <a href="https://www.openstreetmap.org/user/new" target="_blank">sign up here</a> with just an email address.

[munzzyy]

Done in e8ab8ab. Went with your wording, About link included, and moved the note up into the hero right under the download buttons instead of the bottom CTA, so it reads before anyone installs. Dropped the old bottom copy so it doesn't show twice. Also pointed the OpenStreetMap mention in the reporting-page alert at the About page to match. Built clean locally.

[stopflock]

LGTM. @frillweeman ?
I don't think we have a dev build but I looked at the diff and it looks right to my eye

[munzzyy]

Thanks for looking it over, @stopflock. I'm around if @frillweeman wants anything changed — it's just the signup-prompt copy and the conditional around it, so it's easy to adjust.