feat(CF-1812): Use confluence-collab for section-based page editing

Replace inline regex section parser in voice.py with confluence_collab
library (BS4 parsing, 409 conflict retry). Bot now loads section outline
into LLM context when Confluence links are detected.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

voice.py

@@ -279,67 +279,21 @@ async def _confluence_read_page(page_id: str) -> tuple[str, str, int]:
 async def _confluence_update_section(page_id: str, section_heading: str, new_html: str) -> str:
     """Update a section of a Confluence page by heading.
 
-    Finds the section by heading, replaces content up to next same-level heading,
-    PUTs with incremented version.
+    Uses confluence_collab library for BS4 parsing and 409 conflict retry.
     """
     if not CONFLUENCE_URL or not CONFLUENCE_USER or not CONFLUENCE_TOKEN:
         return "Confluence credentials not configured."
-    # Read current page
-    url = f"{CONFLUENCE_URL}/rest/api/content/{page_id}"
-    params = {"expand": "body.storage,version,title"}
-    async with httpx.AsyncClient(timeout=15.0) as client:
-        resp = await client.get(url, params=params, auth=(CONFLUENCE_USER, CONFLUENCE_TOKEN))
-        resp.raise_for_status()
-        data = resp.json()
+    from confluence_collab.client import Auth
+    from confluence_collab.editor import section_update
 
-    title = data["title"]
-    version = data["version"]["number"]
-    body_html = data["body"]["storage"]["value"]
-
-    # Find section by heading (h1-h6) and replace content up to next same-level heading
-    heading_pattern = re.compile(
-        r'(<h([1-6])[^>]*>.*?' + re.escape(section_heading) + r'.*?</h\2>)',
-        re.IGNORECASE | re.DOTALL,
-    )
-    match = heading_pattern.search(body_html)
-    if not match:
-        return f"Section '{section_heading}' not found on page."
-
-    heading_tag = match.group(0)
-    heading_level = match.group(2)
-    section_start = match.end()
-
-    # Find next heading of same or higher level
-    next_heading = re.compile(
-        rf'<h[1-{heading_level}][^>]*>',
-        re.IGNORECASE,
-    )
-    next_match = next_heading.search(body_html, section_start)
-    section_end = next_match.start() if next_match else len(body_html)
-
-    # Replace section content
-    new_body = body_html[:section_start] + new_html + body_html[section_end:]
-
-    # PUT updated page
-    put_data = {
-        "version": {"number": version + 1},
-        "title": title,
-        "type": "page",
-        "body": {
-            "storage": {
-                "value": new_body,
-                "representation": "storage",
-            }
-        },
-    }
-    async with httpx.AsyncClient(timeout=15.0) as client:
-        resp = await client.put(
-            url,
-            json=put_data,
-            auth=(CONFLUENCE_USER, CONFLUENCE_TOKEN),
-        )
-        resp.raise_for_status()
-    return f"Section '{section_heading}' updated successfully."
+    auth = Auth(base_url=CONFLUENCE_URL, username=CONFLUENCE_USER, api_token=CONFLUENCE_TOKEN)
+    result = await section_update(page_id, section_heading, new_html, auth)
+    if result.ok:
+        msg = f"Section '{section_heading}' updated successfully."
+        if result.retries > 0:
+            msg += f" ({result.retries} conflict retries)"
+        return msg
+    return result.message
 
 
 def _build_e2ee_options() -> rtc.E2EEOptions: