Move webmention parsing and authorship into the app

The jonnybarnes/webmentions-parser package is now archived, and its
guzzlehttp/guzzle ^6|^7 constraint was the only thing holding Guzzle
back from 8. Port the parts we use into App\Services\WebMention and
drop the package.

Parser keeps getMentionType and the checkInReplyTo/LikeOf/RepostOf
checks unchanged. Authorship follows the same authorship algorithm,
with some fixes:

- fetch the author page with Laravel's Http client, so tests can fake
  it, and treat connection failures as AuthorshipParserException too
- keep state in locals so one instance can be reused safely
- make the url == uid == author-page check actually compare the
  h-card's uid, rather than an undefined variable

Add direct tests for both, and mark the library as archived on the
projects page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "26051a7c122209f8ee213ca660fd0eb6",
+    "content-hash": "c05d8b5c324f0f2308155a5a65c35a0d",
     "packages": [
         {
             "name": "aws/aws-crt-php",
@@ -1752,57 +1752,6 @@
             },
             "time": "2020-11-29T11:13:10+00:00"
         },
-        {
-            "name": "jonnybarnes/webmentions-parser",
-            "version": "v0.6",
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-                "reference": "cac1acb2b252d6eb611fc5f3a2c6e2265bc86b44",
-                "shasum": ""
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-            "require": {
-                "guzzlehttp/guzzle": "^6.0|^7.0",
-                "mf2/mf2": "~0.4",
-                "php": "^7.3|^8.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "^9.0"
-            },
-            "type": "library",
-            "autoload": {
-                "psr-4": {
-                    "Jonnybarnes\\WebmentionsParser\\": "src"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "CC0-1.0"
-            ],
-            "authors": [
-                {
-                    "name": "Jonny Barnes",
-                    "homepage": "https://jonnybarnes.uk"
-                }
-            ],
-            "description": "A PHP library to parse webmentions from HTML",
-            "keywords": [
-                "html",
-                "indieweb",
-                "microformats",
-                "webmentions"
-            ],
-            "support": {
-                "issues": "https://github.com/jonnybarnes/webmentions-parser/issues",
-                "source": "https://github.com/jonnybarnes/webmentions-parser/tree/v0.6"
-            },
-            "time": "2020-11-29T11:40:36+00:00"
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