Add a favicon and rework the Design page

Blogs had no icon at all, and browsers probing /favicon.ico ended up
rendering the 404 page. Ship a default paper & ink icon (svg + png) and
let each blog replace it from the Design page; /favicon.ico now serves
the default or redirects to the blog's own image. ICO uploads accepted.

The Design page gains colour schemes, reset to defaults, thumbnail
image pickers, jump links and a sticky save bar, plus new options:
heading font, link underline/hover, content box style and padding,
header image height, post dates and format, footer RSS toggle, menu
alignment/style/hover and sidebar width. The Menu card picks the
position with illustrated tiles and shows only the options that apply
to it, using CSS :checked rules rather than JavaScript.

All new defaults reproduce the previous look, so existing blogs are
unchanged until edited. Theme is jsonb, so no migration.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index 6b22a4b..8ccc78a 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ Server-rendered HTML, no JavaScript required, works on old browsers and phones.
 - **Announcements**: blog-wide notices (next meeting, this month's book, a closure)
   shown above or below the posts, or under the menu; each can be hidden without deleting.
 - Every blog has **pages** (Home, About, News, …); each page holds posts.
-- **Design** form: background colour/image, fonts, widths, header, menu position, footer.
+- **Design** form: colour schemes, background colour/image, fonts, link style, content box, header, menu, post dates, footer, site icon (favicon).
 - Changes are live immediately: save, then refresh the blog tab.
 - A **superadmin** creates bloggers, resets passwords, disables or deletes accounts.
 - The **root domain is itself a blog**, owned by the superadmin and managed like any other.