fix(collectives): surface failed requests instead of passing them on

Three findings from the Copilot review on #159, all the same shape: a failed
request was treated as a successful one.

get_page_content only special-cased 404. Any other failure was handed back as
if the response body were the page's markdown - in practice a DAV error
document, which the agent would then summarize as page content. The 404
contract is unchanged and still comes first; every 4xx and 5xx now raises.

update_page_content discarded the PUT response entirely and always reported
success, so a refused write looked like a completed one to the agent and to
the user. The realistic case is the one the tool's own docstring warns about:
a page held open in the real-time editor is locked, the write comes back 423,
and the tool said it had gone through.

Both use response.raise_for_status(). The review suggested it verbatim for the
read; the write is the same problem and gets the same treatment. It is also
what nc_py_api's own check_error() uses internally. Its message carries status,
reason and URL, and graph.py's handle_tool_error hands repr() of the exception
back to the model, so the agent sees what failed rather than a bare status
code. 2xx multi-status responses do not raise.

is_available caught bare, which also swallows asyncio.CancelledError and turns
a cancellation during tool discovery into "Collectives unavailable" while
discovery carries on - freezing an incomplete tool list in the 60-second cache
around it. It now catches Exception, so cancellation propagates.

Signed-off-by: Pavlinchen <69079839+Pavlinchen@users.noreply.github.com>

Author: Pavlinchen

ex_app/lib/all_tools/collectives.py

@@ -116,6 +116,7 @@ async def get_page_content(collective_id: int, page_id: int):
 		})
 		if response.status_code == 404:
 			return ''
+		response.raise_for_status()
 		return response.text
 
 	@tool
@@ -171,9 +172,10 @@ async def update_page_content(collective_id: int, page_id: int, content: str):
 		url = await _page_webdav_url(user_id, page)
 		body = _strip_ai_disclaimer(content).rstrip()
 		stamped = f"{body}\n\n{_AI_DISCLAIMER}\n" if body else f"{_AI_DISCLAIMER}\n"
-		await nc._session._create_adapter(True).request('PUT', url, headers={
+		response = await nc._session._create_adapter(True).request('PUT', url, headers={
 			'Content-Type': 'text/markdown',
 		}, data=stamped)
+		response.raise_for_status()
 		return json.dumps({'status': 'success', 'page_id': page_id})
 
 	@tool
@@ -281,6 +283,6 @@ def get_category_name():
 async def is_available(nc: AsyncNextcloudApp):
 	try:
 		await nc.ocs('GET', '/ocs/v2.php/apps/collectives/api/v1.0/collectives')
-	except:
+	except Exception:
 		return False
 	return True