Fix CSRF exemption and array-input crash on revocation/introspection

An Opus code review of the branch caught two real bugs the test suite
structurally couldn't see:

- /revocation and /introspect were never added to bootstrap/app.php's
  CSRF except list, so both were fully broken (403) for any real
  external client, despite every feature test passing — CSRF
  verification is short-circuited entirely while running tests.
  Verified live against the running app before and after the fix, and
  added a regression test that asserts against the actual configured
  exemptions rather than relying on request-time behavior that tests
  can't exercise.

- An array-shaped `token` param (e.g. token[]=a&token[]=b) crashed
  both endpoints with a 500, since this app promotes PHP warnings
  ("Array to string conversion") to exceptions. Fixed at the shared
  root, MicropubToken::findActive(), which also closes the same latent
  hole in VerifyMicropubToken's access_token param that predates this
  branch. Verified live and covered with regression tests.

Also applied the review's lower-severity findings: added the missing
introspection_endpoint Link header and metadata test assertions,
removed the now-dead is_string($scopes) array branch in the Micropub
handlers and media controller (scope is unconditionally a string from
the DB now, this guarded against a JWT-array-claim shape that can no
longer occur), dropped a redundant #[Table] model attribute, sized
token_hash to its actual 64-char length, and removed a one-off inline
style in the admin view.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014625MfkGZ7GVdbqKme4a8L

tests/Feature/TokenServiceTest.php

@@ -71,4 +71,18 @@ class TokenServiceTest extends TestCase
             'error_description' => 'The provided token did not pass validation',
         ]);
     }
+
+    /**
+     * Request input for a "string" field can be sent as an array
+     * (e.g. token[]=a&token[]=b). Casting that to string throws in this app
+     * (warnings are promoted to exceptions), so findActive() must guard
+     * against it rather than assume its caller already validated the type.
+     */
+    #[Test]
+    public function find_active_treats_non_string_input_as_absent(): void
+    {
+        $this->assertNull(MicropubToken::findActive(['a', 'b']));
+        $this->assertNull(MicropubToken::findActive(null));
+        $this->assertNull(MicropubToken::findActive(123));
+    }
 }