fix: phone leak, field-by-value detection, strict Flamingo email fallback

Three pilot-surfaced issues in one pass:

1. PhoneParser regex used '\s' in the candidate character class, so a
   digit on a following flattened line bled into the phone. '+7977
   6277470\n1' (phone + trailing checkbox value) parsed as 12 digits,
   producing '+797762774701'. Replaced '\s' with a literal space so
   newlines/tabs stop the candidate.

2. Custom-themed forms don't use 'your-name' / 'your-email' keys
   (washanyanya.ru has text-211 / text-212 / name_user). Added
   FieldDetector::find_name + find_email as fallbacks. Classifier
   and MessageFormatter now call them if no standard key matches,
   so 'Александр' in text-211 is recognised as a cyrillic name and
   scored / displayed accordingly.

3. FlamingoHelper copied '_from_email' into 'your-email' without
   validating it. Flamingo derives that meta from whatever field it
   considers "first"; on phone-first forms it ends up holding the
   phone number. Now we only copy _from_email if it contains '@',
   and dropped the _from_name shortcut entirely — FieldDetector
   handles the name via the actual field values.

Tests: +1 FieldDetectorTest (13 cases); +2 PhoneParserTest cases for
newline/tab bleeds; +1 ClassifierTest case; +1 MessageFormatterTest
case for custom field keys. Full suite 53/53 green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

includes/class-flamingo-helper.php

@@ -56,12 +56,17 @@ final class FlamingoHelper
                 $out[$name] = $val;
             }
         }
-        // Convenience: expose Akismet's "from" name / email so the formatter's
-        // standard slots aren't empty for most submissions.
-        $from_name = (string)get_post_meta($post->ID, '_from_name', true);
+        // Flamingo's "_from_name" and "_from_email" are derived heuristically
+        // from whatever field the plugin considers the "first" — on custom
+        // forms without dedicated email / name fields this produces garbage
+        // (e.g. phone number under _from_email). Only trust _from_email if
+        // it actually looks like an email; _from_name is not trustworthy at
+        // all, so leave it to FieldDetector (run by Classifier / Message-
+        // Formatter) to identify a name from any field value.
         $from_email = (string)get_post_meta($post->ID, '_from_email', true);
-        if ($from_name !== '' && !isset($out['your-name'])) $out['your-name'] = $from_name;
-        if ($from_email !== '' && !isset($out['your-email'])) $out['your-email'] = $from_email;
+        if ($from_email !== '' && strpos($from_email, '@') !== false && !isset($out['your-email'])) {
+            $out['your-email'] = $from_email;
+        }
         return $out;
     }