Fix docstrings in ingest/pipeline.py

[mercael91]

Closes #130. Fixed docstrings in ingest/pipeline.py to provide meaningful descriptions.

[Paul-Kyle]

Thanks for picking this up, and I'm afraid I can't take this one.

The diff is +11 / −326: it replaces almost all of palinode/ingest/pipeline.py with two new
functions, process_url and process_schema, whose bodies are # Function implementation. That
removes the real ingestion code along with is_safe_url, which is the SSRF guard on URL fetching —
so merging it would drop a security control and the module's actual behaviour.

The issue was narrower than it may have read: five specific docstring lines needed rewriting, and
nothing else in the file was meant to change. #131 covers that exact five-line scope and was opened
first.

If you'd like to contribute, the thing I'd genuinely ask is a quick read of the diff before opening —
git diff --stat alone would have shown 326 deletions on an issue about documentation, and that
signal is worth more than any review I can give afterwards. Tooling assistance is welcome here; we
just ask that the diff be checked before it goes out.

The good-first-issue lane is empty at the moment, which is our problem and not yours. I'll be seeding
more shortly and I'm happy to point you at one when I do.

[Paul-Kyle]

Following up as promised, and with an apology attached.

I said the good-first-issue lane was empty and that I'd point you at something. It turns out I had
also scoped #130 badly — twice. I searched for a keyword instead of reading the docstrings, told
everyone the prose appeared in no other file, and it does: palinode/indexer/watcher.py has about
seventeen lines of it across the module docstring and six methods.

That's #135, and I've reserved it for you until 22 August. It's assigned to me as a placeholder so
nobody else picks it up in the meantime — comment on it and I'll reassign it to you properly.

#131 landed the first pass in the other file, so there's a worked example in main of exactly the
register to aim for. It's docstrings only, one file, and I've listed every line.