*: drop unused runtime opam deps (lint sweep)

Per-package removal of opam runtime [depends] entries that
[monopam lint] flagged as unused -- packages declared as runtime deps
but referenced by no library [(libraries ...)] stanza in any of the
package's main lib/exec dune files (and not pulled in transitively
via META).

Verified each removal by running [dune build] (and [dune test] for
packages with a test suite) before moving on. No code changes -- only
dune-project [(depends ...)] lists.

Packages touched:

- ca-certs drop nox-crypto
- dupfind drop bos
- merlint drop nox-json (still pulled in via nox-opam.bytesrw)
- monopam drop bytesrw, requests
- monopam-info drop nox-loc, nox-sexp
- ocaml-agent drop nox-tty
- ocaml-atproto-oauth drop did-plc, did-web
- ocaml-auth drop nox-json
- ocaml-cam drop ptime
- ocaml-claude drop nox-loc
- ocaml-cop1 drop logs
- ocaml-did drop bytesrw
- ocaml-ewah drop bytesrw
- ocaml-freebox drop ipaddr
- ocaml-gauth drop base64, ptime
- ocaml-gdocs drop oauth
- ocaml-gsheets drop oauth
- ocaml-gslides drop oauth
- ocaml-hap drop nox-crypto-rng
- ocaml-jailhouse drop fmt

Generated [.opam] files updated by dune accordingly.

Remaining unused warnings ([ocaml-jwt], [ocaml-meross], [ocaml-oci],
[ocaml-pid1], [ocaml-publicsuffix], [ocaml-punycode], [ocaml-pus],
[ocaml-qemu], [ocaml-rego], [ocaml-requests], [ocaml-sbom],
[ocaml-scc], [ocaml-sdls], [ocaml-sigstore], [ocaml-sle],
[ocaml-spacedata], [ocaml-stix], [ocaml-vz], [prune], plus the
[ocaml-ccsds] meta-package and a handful of others) will follow in a
later pass once each is verified against its tests; this commit
covers only the ones I built and tested in this session.