[truegoodcraft]

Changes

• Adds a "Support us" link to the main navigation, after "Start a directory". It points to /#support and appears only when the support section is configured.
• Styles it as an outlined button in the brick accent colour, so it stands out from the plain text links. At narrow widths it wraps onto its own line.
• The browser test checks the new link.

Verification

• tsc --noEmit passes.
• Project-site unit and contract tests: 4 passed.
• Project-site browser test in Chromium passes, including the 320px no-horizontal-scroll check.