#25 + submit buttons on issues/pulls pages

Context: /new-issue.html + /new-pr.html exist but nothing links to them — a human browsing issues/pulls has no visible path to submit. Agents use agents.md; humans need a button. Tasks:

1. Issues index + pulls index: prominent + button (link, Tokyo Night accent, >=40px target) to /new-issue.html + /new-pr.html respectively. Label it + New issue / + New PR prompt (icon + text, not icon-only — humans need words). Also link from empty states ("No issues yet" → suggest submitting).
2. Submission pages themselves: confirm they explain the deal in human words (what happens: private suggestion, ack id, license grant summary + link to full text, no account needed). Keeping the full license checkbox (already there) — add a one-line plain summary above it.
3. Detail pages (single issue/PR): no button needed (keep tiny) — index-level only.
4. Tests: index pages contain the + links with correct hrefs; empty states link to forms; submission pages contain license summary + checkbox. Success rubric:

• A human can go issues → + → submit with zero prior knowledge; same for PRs. Swarm: Owlette. Branch m6/submit-buttons. MUST branch after #17 merges (same templates).