ActivityPub in OCaml using jsont/eio/requests

Fix build warnings and odoc documentation errors

- Add explicit unix library dependency to dune files (html5rw, tomlt)
- Fix odoc heading levels ({0 -> {1) in imap subject.mli and thread.mli
- Fix code block indentation in subject.mli and h2_stream.mli
- Change unresolved module references to plain text (Bytesrw_unix,
Bytesrw_eio, Webfinger.Jrd.t)
- Fix @raise tags to use Error instead of Error.t
- Escape @mention/@mentions text in poe docs to avoid unknown tag warnings
- Remove unreachable flag_perm rule and redundant list_mailbox production
from IMAP grammar

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

+2 -1
+2 -1
lib/client/apubt.mli
··· 189 189 @raise E on lookup failure *) 190 190 191 191 val lookup_raw : t -> string -> Webfinger.Jrd.t 192 - (** [lookup_raw client acct] performs a Webfinger lookup returning the raw JRD. 192 + (** [lookup_raw client acct] performs a Webfinger lookup returning the raw 193 + [Webfinger.Jrd.t] from the webfinger library. 193 194 194 195 This is more efficient when you only need to extract specific fields 195 196 and don't need the full {!Proto.Webfinger.t} type.