Each README's 'opam install <pkg>' instructions now match the post-rename
opam package names. Auto-generated by 'monopam lint --fix' after the
nox-* prefix landed on the underlying packages.

Renames 35 packages to make blacksun forks distinguishable from their
opam-repository upstreams. Module names (Git.x, Tls.x, ...) stay bare;
opam package names and dune (public_name) findlib references move to
nox-X. After this commit, zero local package names overlap with
opam-repository.

Renamed:
- nox-git, nox-irmin
- nox-crypto, nox-crypto-pk, nox-crypto-rng, nox-crypto-ec
- nox-tls, nox-tls-eio, nox-tar, nox-tar-eio, nox-tty, nox-tty-eio
- nox-arp, nox-ca-certs, nox-cbor, nox-cookie, nox-crc, nox-csv
- nox-gpt, nox-hkdf, nox-http, nox-jwt, nox-kdf, nox-loc
- nox-memtrace, nox-pds, nox-sexp, nox-slack, nox-toml
- nox-websocket, nox-x509, nox-xdge, nox-yaml

Also drops orphan tar-mirage and tar-unix opam templates that had no
matching package stanza.

Each fork's dune-project (source ...) now matches the canonical
upstream URL recorded in sources.toml, so the generated dev-repo:
in opam-repository points users at the real home rather than the
in-monorepo collaboration fork. Where Thomas is doing maintenance
on the fork but isn't yet listed, add him to the relevant author
or maintainer fields.

ca-certs -> github mirage/ca-certs
(added Thomas to authors and maintainers)
ocaml-cbor -> tangled anil.recoil.org/ocaml-cbort
ocaml-cookie -> tangled anil.recoil.org/ocaml-cookeio
ocaml-json -> github dbuenzli/jsont
ocaml-jwt -> tangled anil.recoil.org/ocaml-jsonwt
ocaml-tar -> github mirage/ocaml-tar
(added Thomas to maintainers)
ocaml-toml -> tangled anil.recoil.org/ocaml-tomlt
ocaml-yaml -> tangled anil.recoil.org/ocaml-yamlt

Pure formatting changes from `dune fmt`: doc comment placement moves
from above the binding to below it for `type`s, multi-line `match`
expressions collapse onto one line where they fit, and infix operator
applications pick up spaces (`Soup.($?)` -> `Soup.( $? )`). No
semantic changes.

Object combinators: [Object.mem] -> [Object.member], [Object.opt_mem]
-> [Object.opt_member], [Object.case_mem] -> [Object.case_member]. The
sibling submodules [Object.Mem] / [Object.Mems] become
[Object.Member] / [Object.Members]. RFC 8259 §4 calls these
"name/value pairs, referred to as the members", so mirror the spec
name rather than the shortened [mem].

[Object.finish] -> [Object.seal]. "Seal" reads as "close the map, no
more members added", which is what the operation does.

Value constructors/queries: [Value.mem] (function) -> [Value.member];
[Value.mem_find] -> [Value.member_key]; [Value.mem_names] ->
[Value.member_names]; [Value.mem_keys] -> [Value.member_keys].
[type mem = ...] -> [type member = ...]; [type object'] still points
at [member list].

Downstream (~80 files across slack, sbom, stripe, sigstore, requests,
claude, irmin, freebox) updated via perl-pie. dune build clean,
dune test ocaml-json clean.