fix(gateway): accept CJK full-width punctuation as MEDIA path terminators

MEDIA_TAG_CLEANUP_RE (and MEDIA_EXTENSIONLESS_TAG_RE) only recognized
ASCII terminators after a MEDIA:<path> tag. Chinese-language agent
output naturally writes MEDIA:D:\...\zhibao.pdf（782.6 KB）or ...pdf：内容 —
the full-width punctuation failed the trailing lookahead and the
attachment was silently dropped (cron even reported 'delivered') (#88038).

Both lookaheads now accept a CJK full-width terminator set (（）〈〉《》：，。；
！？、curly quotes【】) alongside the ASCII set. The #68773 adjacent-tag
splitting guard is covered by a regression test.

gateway/platforms/base.py

@@ -1939,11 +1939,17 @@ _MEDIA_EXT_ALTERNATION = "|".join(
 # guard keeps multi-part extensions intact — for ``archive.tar.gz`` the
 # ``.`` after ``tar`` is followed by ``g``, so the match must extend to
 # ``.gz`` instead of stopping early at ``.tar``.
+# CJK full-width punctuation accepted as MEDIA path terminators, mirroring the
+# ASCII set in the looka below. Chinese-language agent output naturally writes
+# ``MEDIA:D:\path\早报.pdf（782.6 KB）`` or ``MEDIA:...pdf：内容`` — without
+# these, the lookahead fails and the attachment is silently dropped (#88038).
+_MEDIA_CJK_TERMINATORS = "（）〈〉《》：，。；！？、\u201c\u201d\u2018\u2019【】"
+
 MEDIA_TAG_CLEANUP_RE = re.compile(
     r'''[`"'*_]{0,3}MEDIA:\s*'''
     r'''(?P<path>`[^`\n]+?`|"[^"\n]+?"|'[^'\n]+?'|'''
     r'''(?:~/|/|[A-Za-z]:[/\\])\S+?(?:[^\S\n]+\S+?)*?\.(?:''' + _MEDIA_EXT_ALTERNATION + r'''))'''
-    r'''(?=[\s`"'*_,;:)\]}\[]|MEDIA:|\.(?:\s|$)|$)[`"'*_]{0,3}\.?''',
+    r'''(?=[\s`"'*_,;:)\]}\[''' + _MEDIA_CJK_TERMINATORS + r''']|MEDIA:|\.(?:\s|$)|$)[`"'*_]{0,3}\.?''',
     re.IGNORECASE,
 )
 
@@ -1979,7 +1985,7 @@ MEDIA_EXTENSIONLESS_TAG_RE = re.compile(
     r'''[`"'*_]{0,3}MEDIA:\s*'''
     r'''(?P<path>`[^`\n]+`|"[^"\n]+"|'[^'\n]+'|'''
     r'''(?:~/|/|[A-Za-z]:[/\\])[^\s\n`"']+?)'''
-    r'''(?=[`"'\s,;:)\]}]|MEDIA:|$)'''
+    r'''(?=[`"'\s,;:)\]}''' + _MEDIA_CJK_TERMINATORS + r''']|MEDIA:|$)'''
     r'''[`"'*_]{0,3}\s*''',
     re.IGNORECASE,
 )

tests/gateway/test_media_tag_cleanup.py

@@ -34,3 +34,65 @@ class TestMediaTagCleanup:
         assert "/tmp/chart.png" not in stripped
 
 
+class TestMediaTagCjkTerminators:
+    """#88038: CJK full-width punctuation after a MEDIA path is a valid
+    terminator, exactly like its ASCII counterparts. Chinese-language agent
+    output naturally writes ``MEDIA:D:\\...\\zhibao.pdf（782.6 KB）`` — the
+    ASCII-only lookahead silently dropped the attachment."""
+
+    def test_full_width_suffixes_terminate_the_path(self):
+        from gateway.platforms.base import MEDIA_TAG_CLEANUP_RE
+
+        cases = [
+            "MEDIA:D:/workspace/out/report.pdf（782.6 KB）",
+            "MEDIA:D:/workspace/out/report.pdf：内容",
+            "MEDIA:D:/workspace/out/report.pdf。",
+            "MEDIA:D:/workspace/out/report.pdf，下一条",
+            "MEDIA:D:/workspace/out/report.pdf；",
+            "MEDIA:D:/workspace/out/report.pdf！",
+            "MEDIA:D:/workspace/out/report.pdf？",
+            "MEDIA:D:/workspace/out/report.pdf、",
+            "MEDIA:D:/workspace/out/report.pdf”",
+            "MEDIA:D:/workspace/out/report.pdf’",
+        ]
+        for text in cases:
+            m = MEDIA_TAG_CLEANUP_RE.search(text)
+            assert m is not None, text
+            assert m.group("path").endswith(".pdf"), (text, m.group("path"))
+
+    def test_real_chinese_cron_delivery_line(self):
+        from gateway.platforms.base import MEDIA_TAG_CLEANUP_RE
+
+        text = (
+            "## 交付物\n\n- **PDF 早报**："
+            "MEDIA:D:/workspace/zaobao/output/早报_2026-08-16.pdf（782.6 KB）"
+        )
+        m = MEDIA_TAG_CLEANUP_RE.search(text)
+        assert m is not None
+        assert m.group("path") == "D:/workspace/zaobao/output/早报_2026-08-16.pdf"
+
+    def test_ascii_terminators_still_work(self):
+        from gateway.platforms.base import MEDIA_TAG_CLEANUP_RE
+
+        for text in (
+            "MEDIA:/tmp/report.pdf",
+            "MEDIA:/tmp/report.pdf 782 KB",
+            "MEDIA:/tmp/report.pdf, next",
+        ):
+            m = MEDIA_TAG_CLEANUP_RE.search(text)
+            assert m is not None and m.group("path").endswith(".pdf"), text
+
+    def test_adjacent_tags_still_split(self):
+        """#68773 guard: the widened class must not let tags glue together."""
+        from gateway.platforms.base import MEDIA_TAG_CLEANUP_RE
+
+        found = MEDIA_TAG_CLEANUP_RE.findall("MEDIA:/a.pngMEDIA:/b.png")
+        assert list(found) == ["/a.png", "/b.png"]
+
+    def test_extensionless_variant_accepts_full_width_colon(self):
+        from gateway.platforms.base import MEDIA_EXTENSIONLESS_TAG_RE
+
+        m = MEDIA_EXTENSIONLESS_TAG_RE.search("MEDIA:/tmp/Caddyfile：内容")
+        assert m is not None and m.group("path") == "/tmp/Caddyfile"
+
+