release: v1.5.1 — bind guard failed open, [full] would not install, DIMSCALE did nothing

Three defects found after 1.5.0 reached PyPI, two of them by the adversarial
pass over the rewritten README.

The HTTP bind guard failed open on the launch path it was written for.
`_guarded_run_async` read the bind address from the `host` kwarg and treated an
absent one as loopback. It is not: `fastmcp run` forwards that kwarg only when
`--host` was passed, and fastmcp otherwise resolves the host from
`fastmcp.settings.host`, which is environment-backed. So

    FASTMCP_HOST=0.0.0.0 fastmcp run server.py:mcp --transport http

bound every interface -- 149 tools including file open/save and AutoCAD command
execution, no token -- while the guard inspected the literal "127.0.0.1" and
waved it through. v1.4.0's changelog claimed this guard "fires on every launch
path"; it fired, and looked at the wrong host. It now resolves the effective
host, and warns rather than staying silent if it cannot.

`[com]` and `[full]` could not be installed off Windows. Both listed
`pywin32>=306` with no environment marker, and pywin32 publishes Windows wheels
and no sdist, so `pip install autocad-mcp-pro[full]` died at resolution on
Linux and macOS -- and `[full]` is the extra the README recommended to
contributors. CI never caught it because every Linux lane installs `[pdf]` or
syncs from uv.lock, whose resolution markers hide the gap. Both entries carry
`; sys_platform == "win32"` now, with a release-consistency test to keep them.

`drawing_settings({"dimscale": ...})` reported success and changed nothing
headlessly. It writes `$DIMSCALE`, which is what AutoCAD reads when it draws a
dimension, so the call worked on COM; ezdxf renders from the dimstyle table
entry and never consults the header. One call, one reported success, two
different drawings. The header value now folds into the per-dimension override
on all five dimension tools -- including `dimension_aligned` and
`dimension_angular`, which do not share the tolerance-override path and the
obvious fix would have missed. DIMSCALE 1.0 writes nothing.

README: every engine-conditional family in the feature table now says which
engine (boundary tracing, WIPEOUT/REVCLOUD/MTEXT masks, CHSPACE, typed hatch
edge paths, headless undo), and the checkout install line stopped recommending
an extra that could not resolve on the reader's platform.

1257 passed, 1 xfailed. 1.5.0 is to be yanked: its diameter and radius callouts
put wrong numbers on drawings at default settings.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "autocad-mcp-pro"
-version = "1.5.0"
+version = "1.5.1"
 description = "Production-grade AutoCAD MCP server — COM API + ezdxf dual engine"
 readme = "README.md"
 requires-python = ">=3.11"
@@ -74,7 +74,13 @@ Changelog = "https://github.com/U-C4N/Autocad-MCP/blob/main/CHANGELOG.md"
 # renders nothing. Install `[pdf]` (or `[full]`) for rendering on any platform:
 # Pillow comes in transitively as a matplotlib dependency.
 com = [
-    "pywin32>=306",
+    # pywin32 publishes Windows wheels and no sdist, so without this marker
+    # the extra cannot be resolved at all on Linux or macOS -- pip dies at
+    # "no matching distribution" before installing anything. The marker
+    # makes `pip install autocad-mcp-pro[com]` a no-op there instead of a
+    # hard failure, which is the honest outcome: the COM backend needs
+    # Windows, and the server already falls back to ezdxf.
+    'pywin32>=306; sys_platform == "win32"',
     # Win32 window capture for the live-AutoCAD screenshot path.
     "Pillow>=10.0",
 ]
@@ -83,7 +89,10 @@ pdf = [
     "matplotlib>=3.8",
 ]
 full = [
-    "pywin32>=306",
+    # Same marker as `com` above, and for the same reason: `[full]` is the
+    # extra this project recommends to contributors, and it was
+    # uninstallable on every non-Windows machine.
+    'pywin32>=306; sys_platform == "win32"',
     "Pillow>=10.0",
     "matplotlib>=3.8",
 ]