docs: OpenCoupon and OpenRecipe.md, the first two niche specs (#165)

Anthony: every top-level nichedb.dev niche may need its own open<niche>
spec so the serve-your-own-file pattern scales across industries. These
are the two he named first.

OpenCoupon: one JSON file a merchant serves at
/.well-known/opencoupon.json about what is on offer right now: every
code, sale and shipping threshold with kind (percent, amount, shipping,
bogo, gift, other), value, scope, min_order, dates, status, per-customer
and region limits. Expired coupons stay in the file so a directory
learns a code died from the one party that knows. No affiliate links,
no redemption, no votes. First reader: nichedb.dev/c/deals.

OpenRecipe.md: one Markdown file that is a recipe, in the OpenProfile.md
and OpenResume.md style: a summary block (Serves, Prep, Cook, Cuisine,
Course, Diet, Author, Source, Image), a description line, Ingredients
and Steps as written, Notes, Nutrition per serving. Served next to the
page, linked with rel="openrecipe", or indexed at
/.well-known/openrecipe.md. A one-way mapping to schema.org/Recipe:
the JSON-LD is generated from the Markdown, never the reverse.

Both registered in DOC_SLUGS, NAV, STATIC_ROUTES and llms.txt.


Claude-Session: https://claude.ai/code/session_014cmNRtR2vL1p89dbVQ7FZJ

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

apps/logicsrc-web/src/components/site-shell.tsx

@@ -24,6 +24,8 @@ const NAV: Array<{ href: string; label: string; external?: boolean }> = [
   { href: "/openbandwidth", label: "OpenBandwidth" },
   { href: "/openfile", label: "OpenFile" },
   { href: "/opendisk", label: "OpenDisk" },
+  { href: "/opencoupon", label: "OpenCoupon" },
+  { href: "/openrecipe", label: "OpenRecipe.md" },
   { href: "/#cli", label: "CLI" },
   { href: "/docs", label: "Docs" },
   { href: "/blog", label: "Blog" },