P6: quote posts, received and sent (FEP-044f and the older keys)

- Received quotes: read from `quote`, `quoteUrl`, `quoteUri`, `_misskey_quote` or a FEP-e232 Link tag; the quoted post
  is fetched once; a quoteAuthorization stamp is verified field by field on the quoted author's origin; a consent
  quote without a stamp is pending; an older-key quote of a public post is shown; Delete of a stamp revokes. Counts
  and a `quote` notification follow the accepted state. The `quote-inline` fallback survives sanitising and is removed
  from content when the real quote is shown.
- Personas quote through `quoted_status_id`: posts that state a quote policy get a QuoteRequest and stay pending until
  an Accept brings a stamp we can verify, then an Update adds quoteAuthorization; posts that state none are quoted
  the older way, without `quote`; another persona's posts cannot be quoted yet (we issue no stamps). Quoting posts
  are delivered to the quoted author too.
- Mastodon API: Status.quote (with the quoted status one level deep), quotes_count, quote_approval from the remote
  policy, GET /api/v1/statuses/:id/quotes, `quote` notifications, and api_versions.mastodon = 7.

Checked live: GoToSocial's author-only quote policy is respected.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

tools/pasture/interop.sh

@@ -114,6 +114,11 @@ gts_poll_on_pp=$(curl -s -H "$PH" "$P/api/v1/timelines/home" | j "print(next(s['
 curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/polls/$gts_poll_on_pp/votes" -d 'choices[]=0'
 until_true 20 '[ "$(gcurl -s -H "$GH" "$G/api/v1/statuses/$gts_poll" | j "print(d[\"poll\"][\"options\"][0][\"votes_count\"])")" = "1" ]' && ok "alice's vote counts on GoToSocial" || ko "vote not counted on GoToSocial"
 
+echo "quotes"
+quote_target=$(curl -s -H "$PH" "$P/api/v1/timelines/home" | j "print(next(s['id'] for s in d if 'red or blue' in s['content']))")
+[ "$(curl -s -o /dev/null -w '%{http_code}' -X POST -H "$PH" $P/api/v1/statuses -d "status=quoting&quoted_status_id=$quote_target")" = "422" ] \
+	&& ok "GoToSocial's author-only quote policy is respected" || ko "quoted a post whose author forbids it"
+
 echo "link previews"
 linked=$(curl -s -X POST -H "$PH" $P/api/v1/statuses --data-urlencode 'status=have a look https://gts.test/@gtsuser' -d 'visibility=public' | j "print(d['id'])")
 until_true 45 '[ -n "$(curl -s -H "$PH" "$P/api/v1/statuses/$linked" | j "print((d[\"card\"] or {}).get(\"title\") or \"\")")" ]' && ok "the server builds a card for a linked page" || ko "no card for the linked page"