Play Framework

feat: ship favicon.ico alongside favicon.png + add docviewer favicon

Browsers auto-request /favicon.ico at the site root regardless of any
HTML <link rel="icon"> tag. Until now the codebase only shipped
favicon.png in three locations (app-skel, console, secure modules)
plus a defensive routes-level 404 in the app-skel to silence the
auto-request. This commit ships an actual favicon.ico in those same
locations (generated from the existing 16x16 PNGs via ImageMagick),
adds the missing docviewer module favicon, and updates the templates
to reference both formats.

Changes
- New favicon.ico files in the four locations (app-skel/public,
  console/public, secure/public, docviewer/public/playmanual). All
  16x16 RGBA, MS Windows ICO format.
- New favicon.png in docviewer/public/playmanual (copied from
  app-skel — the docviewer didn't have one before).
- App-skel conf/routes: replace the "GET /favicon.ico  404" line
  with "GET /favicon.ico  staticFile:/public/favicon.ico" so fresh
  apps actually serve the icon.
- App-skel app/views/main.html: add <link rel="shortcut icon"
  type="image/x-icon" href="/public/favicon.ico"> alongside the
  existing PNG <link>.
- Console module templates (index/repl/db .html): same dual-link
  pattern.
- Docviewer templates (page/cheatSheet/releases .html): NEW —
  add both <link rel="icon" type="image/png"> and <link
  rel="shortcut icon" type="image/x-icon"> referencing the new
  /public/playmanual/favicon.{png,ico} pair. The docviewer had no
  favicon at all before.

Modern browsers honor the higher-quality PNG via <link rel="icon">
for tab rendering; the ICO at /favicon.ico covers the auto-request
fallback path that older bookmark / shortcut managers expect.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>