build: read version from _const.py, drop phantom scipy/pandas deps

Single source of truth for the package + pinned solver versions in
src/otko/_const.py (hatch dynamic version). scipy/pandas were listed in
[gui] but never imported. mypy strict mode rescoped to
core/services/viewmodels; tomli added for tomllib-less Pythons.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "otko"
-version = "0.1.0"
+dynamic = ["version"]
 description = "OTKO — a modern, SAP2000-style desktop GUI for OpenSeesPy."
 readme = "README.md"
 requires-python = ">=3.10"
@@ -42,10 +42,6 @@ gui = [
     "vtk>=9.3",
     "pyqtgraph>=0.13",
     "imageio[ffmpeg]>=2.34",
-    # scipy and pandas are listed for forward-compatibility; they are not
-    # currently imported by any module in this repo (phantom deps as of 2026-06-15).
-    "scipy>=1.11",
-    "pandas>=2.1",
 ]
 dev = [
     "pytest>=7.4",
@@ -55,6 +51,7 @@ dev = [
     "mypy>=1.8",
     "pre-commit>=3.6",
     "hatch>=1.9",
+    "tomli>=2.0; python_version < '3.11'",
 ]
 docs = [
     "sphinx>=7.2",
@@ -72,6 +69,9 @@ Issues = "https://github.com/ogunc/otko/issues"
 [tool.hatch.build.targets.wheel]
 packages = ["src/otko"]
 
+[tool.hatch.version]
+path = "src/otko/_const.py"
+
 # ─────────── Ruff ───────────
 [tool.ruff]
 line-length = 100
@@ -97,12 +97,13 @@ quote-style = "double"
 # ─────────── Mypy ───────────
 [tool.mypy]
 python_version = "3.10"
-strict = true
-warn_unused_ignores = true
-warn_return_any = true
-disallow_untyped_defs = true
+warn_unused_configs = true
 plugins = []
 
+[[tool.mypy.overrides]]
+module = ["otko.core.*", "otko.services.*", "otko.viewmodels.*"]
+strict = true
+
 [[tool.mypy.overrides]]
 module = ["openseespy.*", "pyvista.*", "pyvistaqt.*", "vtk.*", "pyqtgraph.*"]
 ignore_missing_imports = true
@@ -121,3 +122,8 @@ markers = [
 branch = true
 source = ["src/otko"]
 omit = ["src/otko/views/*"]  # GUI excluded from coverage targets
+
+[tool.coverage.report]
+exclude_lines = ["if TYPE_CHECKING:", "raise NotImplementedError"]
+# Conservative floor for the headless suite; raise deliberately with evidence.
+fail_under = 50