doc create fails with pydantic ValidationError: CreatePage.description_html required

[LouisLau-art]

Describe the bug
planecli doc create crashes with a pydantic ValidationError before any request is sent, because CreatePage(name=title) is constructed without the description_html field, which is required (no default) in the current plane-sdk.

To Reproduce

planecli doc create --title "Test doc" --content "hello" -p SOME_PROJECT

Expected behavior
A document is created (or at least the request is attempted).

Actual behavior

pydantic_core._pydantic_core.ValidationError: 1 validation error for CreatePage
description_html
  Field required [input_value={'name': 'Test doc'}, input_type=dict]

Environment

• planecli 0.5.1
• plane-sdk 0.2.21
• Python 3.11

Root cause
In src/planecli/commands/documents.py (create command):

page_data = CreatePage(name=title)
if content:
    page_data.description_html = f"<p>{content}</p>"

plane-sdk's CreatePage model (see plane.models.pages) declares description_html: str with no default, so model construction fails immediately. name is the only field that can be passed unconditionally.

Suggested fix

page_data = CreatePage(name=title, description_html="")
if content:
    page_data.description_html = f"<p>{content}</p>"

I can open a PR with this one-line change if you'd like.

Note (may or may not be related)
After applying the fix locally, doc create (and doc ls) on a self-hosted Plane instance returns HTTP 404: Page not found for both project pages and workspace pages endpoints. That may be a separate server-version issue, but flagging in case page support was removed/changed in newer Plane versions.