examples: programs that run, in four languages

Eight of them, each doing something a pipeline actually has to do, and each
starting from something anyone can fetch — a public domain book from Project
Gutenberg, a NASA broadcast, or a sample carried in the file.

Shell, because the tools are filters first: a book to passages and what its
notes cite; a recording to chapter marks, citable passages and the one
ffmpeg call that makes it play on a phone; passages into pgvector and a
search that asks twice and reconciles.

Rust, for the case where the caller already holds the text and a subprocess
would be serialising for nothing. Python, for the shape a pipeline stage
takes once the reading is a library call. TypeScript, for the app side —
chapter marks and deep links, and fusing two rankings in process.

Three of them end with what re-ranking means, because it is two different
things under one name: fusing ranked lists, which is what `rrf` does and
needs no model, and a cross-encoder scoring query and passage together,
which is accurate, slow, and runs over what retrieval already found.

README.md

@@ -48,6 +48,10 @@ Each tool installs by name, so you can take one without taking the rest.
 Each links to its own page: what it does, when you would use it, worked
 examples, options and exit codes.
 
+**→ [Examples](examples/README.md) — programs that run.** A book to
+passages and references, a recording to chapter marks and a copy that plays
+on a phone, and a hybrid search fused, in shell, Rust, Python and TypeScript.
+
 **→ [Recipes](docs/recipes.md) — using these tools together.** A scanned book
 to a searchable passage, a transcript to a citation with a timestamp, vectors
 into pgvector, and hybrid search fused on top.