docs(deps[gp-sphinx]) Preview improved-defaults-reprs branch via uv.sources

why: gp-sphinx PR git-pull/gp-sphinx#36 ships curated parameter and
data-attribute default rendering (source-text reprs, dataclass
factory resolution, long-value truncation, and `:py:class:`-styled
cross-reference links inside default values). Pinning the
gp-sphinx-family deps to that branch via `[tool.uv.sources]` lets
this repo's docs preview the user-visible win before the workspace
release bump propagates the changes via PyPI. After the audit,
libtmux's `<libtmux.constants._DefaultOptionScope object>` defaults
across `Pane._show_option`, `Window._show_option`,
`Session._show_option`, hook dataclasses, etc. drop from 171 ugly
sig-params to 0; `scope=` renders as `DEFAULT_OPTION_SCOPE` linked
to the documented constant.

what:
- Add `[tool.uv.sources]` overrides for gp-sphinx,
  sphinx-autodoc-typehints-gp, sphinx-autodoc-api-style, and
  sphinx-autodoc-pytest-fixtures, all pointing at the
  `improved-defaults-reprs` branch with the appropriate
  monorepo subdirectory.
- Regenerate `uv.lock`; uv resolves all transitive workspace
  siblings (sphinx-fonts, sphinx-gp-opengraph,
  sphinx-ux-autodoc-layout, etc.) from the same commit.
- Revert this commit when gp-sphinx>=0.0.1a18 lands and the
  per-package version pins move forward in the usual workspace
  bump.

Author: tony

pyproject.toml

@@ -106,6 +106,16 @@ libtmux = "libtmux.pytest_plugin"
 requires = ["hatchling"]
 build-backend = "hatchling.build"
 
+[tool.uv.sources]
+# TEMPORARY: pull gp-sphinx-family deps from the improved-defaults-reprs
+# branch on git-pull/gp-sphinx so this PR previews the curated-default
+# rendering work before a release bump propagates the changes via PyPI.
+# Revert this block when gp-sphinx>=0.0.1a18 lands.
+gp-sphinx = { git = "https://github.com/git-pull/gp-sphinx.git", branch = "improved-defaults-reprs", subdirectory = "packages/gp-sphinx" }
+sphinx-autodoc-typehints-gp = { git = "https://github.com/git-pull/gp-sphinx.git", branch = "improved-defaults-reprs", subdirectory = "packages/sphinx-autodoc-typehints-gp" }
+sphinx-autodoc-api-style = { git = "https://github.com/git-pull/gp-sphinx.git", branch = "improved-defaults-reprs", subdirectory = "packages/sphinx-autodoc-api-style" }
+sphinx-autodoc-pytest-fixtures = { git = "https://github.com/git-pull/gp-sphinx.git", branch = "improved-defaults-reprs", subdirectory = "packages/sphinx-autodoc-pytest-fixtures" }
+
 [tool.uv.exclude-newer-package]
 # git-pull packages release in lockstep with their workspaces, so a
 # fresh release blocking on the 3-day cooldown blocks every