feat: link the public roadmap from the chip and the footer

[HuggeK]

The community section shows a "Public roadmap" chip, but nothing on the site actually takes you to that roadmap — the claim wasn't clickable. This makes it one:

• The "Public roadmap" chip in the community section is now a link to docs/roadmap.md in srcfl/ftw, with the site's usual ↗ external marker.
• The footer's Project column gains a Roadmap link to the same document.

Styling details

• .license-line a shares the exact chip styling (.license-line span) so the linked chip renders identically to its neighbours, plus text-decoration: none, a 6px gap for the arrow, and an inverted ink/signal hover so it reads as clickable.
• The inner ↗ span gets its chip padding/border reset so it doesn't render as a nested chip.
• The stylesheet cache-buster is bumped ?v=2 → ?v=3 since sourceful.css changed.

Please give the rendered page a quick human look before merging — the hover state on the chip is the only visual novelty.

🤖 Generated with Claude Code

https://claude.ai/code/session_015HBnpxLWTu2NtekaEPEDGF

[miravoss26]

Makes the marketing site's "Public roadmap" chip and a new footer link actually point somewhere: both now link to srcfl/ftw's docs/roadmap.md.

• Small, well-scoped diff: index.html (chip markup + footer link) and sourceful.css (link styling, hover state, nested-span reset). No JS, no dynamic content, no new external dependency beyond a plain GitHub link.
• Cache-buster bumped ?v=2 → ?v=3 on sourceful.css so browsers actually pick up the style change — correct, easy to forget.
• Nothing for the security lens: no secrets, no injection surface, no auth/network changes.
• No CI configured on this repo (empty status-check rollup), so there's no automated check to lean on for the visual result — the PR body itself flags that and asks for a human look at the hover state before merging, which is the right call for a static marketing site.

Safe to merge from my read, contingent on that quick visual check the author already asked for.