feat: v0.4.1 — ChatGPT tool-output content types and conv_id fix

First real-data export against v0.4.0 surfaced 66 unknown blocks across
three content types — captured live and added.

Added:
- execution_output (Code Interpreter / container.exec / python tool
  output) → tool_result block. output=content.text,
  tool_name=author.name, is_error=metadata.aggregate_result.status,
  summary=metadata.reasoning_title
- system_error → error tool_result with tool_name=author.name
- tether_browsing_display: spinner placeholders (empty result+summary)
  skip silently with DEBUG log; defensive populated-case branch maps
  to tool_result (untested in real data)
- tool_result block schema: optional `summary` field rendered as
  italic line between header and fence
- tool_result rendering: tool_name appears in header when present
  (e.g. `📤 Result: container.exec`); existing tool_name=None calls
  unchanged
- _ROLE_LABELS["tool"] = ("🔧 Tool", "tool")

Fixed:
- chatgpt.normalize_conversation reads `conversation_id` as fallback
  for `id`. Live API uses conversation_id; fixtures use id.
  Pre-fix: empty id in YAML frontmatter and missing context in
  WARNING logs.

Tests: 11 new (192 total, 0 failures). Fixture extended with 4
tool-output cases (execution_output success, empty execution_output
that should skip, system_error, tether_browsing_display spinner).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_exporters.py

@@ -371,6 +371,37 @@ class TestRenderBlocks:
         assert "❌ **Result (error)**" in out
         assert "📤" not in out
 
+    def test_tool_result_with_tool_name_in_header(self):
+        out = render_blocks_to_markdown(
+            [make_tool_result_block("done", tool_name="container.exec")]
+        )
+        assert "📤 **Result: container.exec**" in out
+
+    def test_tool_result_error_with_tool_name(self):
+        out = render_blocks_to_markdown(
+            [make_tool_result_block("503", tool_name="web", is_error=True)]
+        )
+        assert "❌ **Result (error): web**" in out
+
+    def test_tool_result_summary_renders_as_italic_line(self):
+        out = render_blocks_to_markdown(
+            [
+                make_tool_result_block(
+                    "output",
+                    tool_name="container.exec",
+                    summary="Reading skill documentation",
+                )
+            ]
+        )
+        # Summary line is italic, lives between header and fence,
+        # all inside the blockquote prefix.
+        assert "> *Reading skill documentation*" in out
+        # Order: header before summary before fence
+        header_idx = out.index("Result: container.exec")
+        summary_idx = out.index("Reading skill documentation")
+        fence_idx = out.index("output")
+        assert header_idx < summary_idx < fence_idx
+
     def test_image_placeholder_rendering(self):
         out = render_blocks_to_markdown(
             [make_image_placeholder(ref="file-123", source="user_upload")]