Add a real submission form, bypassing the broken Gitea issue-template render

Gitea 1.27.1 on this instance silently ignores the ?template= param for
.github/ISSUE_TEMPLATE/hardware-report.yml — the structured fields never
render, just a blank title/body editor (confirmed live: same URL that's
supposed to load the form shows nothing). Rather than debug Gitea's YAML
issue-forms support, site/report.html is a plain form matching the schema
that builds a title + markdown body (with a ready-to-merge YAML block) and
opens Gitea's issues/new with them pre-filled via query params, which does
work on this instance (verified live).

Verified the full round trip in a real browser: filled the form, submitted,
confirmed the opened Gitea tab has the correct title and a body containing
valid YAML matching every field. Did not actually click "Create Issue" —
no reason to leave a test issue on the tracker.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CONTRIBUTING.md

@@ -2,11 +2,17 @@
 
 Two ways to add a report, pick whichever's easier for you.
 
-## Option A — open an issue (no git needed)
+## Option A — use the report form (no git needed)
 
-[Open a hardware report issue](https://source.archipelago-foundation.org/ssmithx/ArchyHCL/issues/new?template=hardware-report.yml)
-and fill in the form. A maintainer will turn it into a data file and it'll
-show up on the site.
+[Fill in the report form](https://hcl.archipelago-foundation.org/report.html) —
+it opens a pre-filled Gitea issue with a ready-to-merge YAML block for you
+(you'll still need a free Gitea account to post it). A maintainer copies the
+block into a new data file and it shows up on the site.
+
+(The repo's `.github/ISSUE_TEMPLATE/hardware-report.yml` structured issue
+form doesn't render on this Gitea instance — it silently falls back to a
+blank issue instead of showing the fields — so the site form above is the
+supported no-git path, not the raw "New Issue" button.)
 
 ## Option B — open a PR directly