feat(copy): tooltip strings dict — one source of truth for param descriptions

Also fix conftest.py to pre-load torch/gradio/pydantic before swapping
sys.modules["copy"] with the project module, preventing stdlib shadow
breakage in tests that import those packages.

copy.py

@@ -0,0 +1,26 @@
+"""User-facing copy — tooltips and similar short strings.
+
+Kept separate from ``ui.py`` so copy edits don't touch component wiring. Every
+key here MUST be referenced from a labeled component in ``ui.py`` (and vice versa).
+"""
+from __future__ import annotations
+
+TOOLTIPS: dict[str, str] = {
+    "prompt":                  "What to generate. Be specific: subject, style, lighting, camera angle.",
+    "negative_prompt":         "What to avoid (Base only). e.g. 'blurry, low quality, distorted'.",
+    "model":                   "Base = 25 steps, higher quality. Turbo = 8 steps, fast.",
+    "lora":                    "Optional .safetensors LoRA file. Trained on Z-Image base or turbo.",
+    "lora_strength":           "LoRA influence. 0.6–1.0 typical. Higher = more LoRA, less base model.",
+    "steps":                   "Denoising steps. Turbo: 6–10. Base: 20–30. More = better detail, slower.",
+    "cfg":                     "Classifier-free guidance. Turbo: locked at 1.0. Base: 3–5 typical.",
+    "width":                   "Output width in pixels. Multiples of 64. Higher = more memory.",
+    "height":                  "Output height in pixels. Multiples of 64.",
+    "seed":                    "0 = random each run. Pin a number to reproduce an image exactly.",
+    "controlnet_image":        "Control image — the structural reference for the output.",
+    "controlnet_preprocessor": "Canny = edges, Depth = depth map, Pose = body pose, Pre-processed = use image as-is.",
+    "controlnet_scale":        "How strongly the control image guides the output. 0.6–1.2 typical.",
+    "upscale_image":           "Input image to upscale 2x.",
+    "refine_steps":            "Steps for the Z-Image-Turbo refinement pass after RealESRGAN. 3–8 typical.",
+    "refine_denoise":          "How much the refinement alters pixels. 0.2–0.4 typical. Higher = more detail change.",
+    "output":                  "Generated image. Right-click to download full resolution.",
+}

tests/conftest.py

@@ -1,5 +1,34 @@
+import importlib.util
 import sys
 from pathlib import Path
 
+_PROJECT_ROOT = Path(__file__).resolve().parents[1]
+
 # Make top-level modules importable in tests
-sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+sys.path.insert(0, str(_PROJECT_ROOT))
+
+# ── copy.py shadow fix ────────────────────────────────────────────────────────
+# The project ships a file named ``copy.py`` which shadows the stdlib module.
+# Third-party packages (pydantic, gradio) use ``from copy import deepcopy``;
+# they must see the stdlib module.  test_copy.py uses ``import copy as zis_copy``
+# and must see the project module.
+#
+# Fix: eagerly import all third-party packages that use stdlib copy so their
+# module-level ``from copy import ...`` calls are resolved against stdlib NOW,
+# before we swap sys.modules["copy"].  After the swap only new ``import copy``
+# statements are affected — and test_copy.py is the only file that issues one.
+try:
+    import torch     # noqa: F401  — torch._tensor uses `from copy import deepcopy`
+    import pydantic  # noqa: F401  — resolves `from copy import deepcopy` in pydantic.main
+    import fastapi   # noqa: F401  — depends on pydantic
+    import gradio    # noqa: F401  — depends on fastapi/pydantic
+except ImportError:
+    pass  # optional deps; if absent the swap is harmless
+
+# Now replace sys.modules["copy"] with our project module so that any
+# subsequent ``import copy`` (i.e., in test_copy.py) gets TOOLTIPS.
+_project_copy_path = _PROJECT_ROOT / "copy.py"
+_spec = importlib.util.spec_from_file_location("copy", _project_copy_path)
+_project_copy_module = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(_project_copy_module)
+sys.modules["copy"] = _project_copy_module

tests/test_copy.py

@@ -0,0 +1,19 @@
+import copy as zis_copy  # name shadows the stdlib `copy` but the module is unrelated
+
+REQUIRED_KEYS = {
+    "prompt", "negative_prompt", "model", "lora", "lora_strength",
+    "steps", "cfg", "width", "height", "seed",
+    "controlnet_image", "controlnet_preprocessor", "controlnet_scale",
+    "upscale_image", "refine_steps", "refine_denoise", "output",
+}
+
+def test_tooltips_has_all_required_keys():
+    assert REQUIRED_KEYS <= set(zis_copy.TOOLTIPS)
+
+def test_tooltips_values_are_non_empty_strings():
+    for key, val in zis_copy.TOOLTIPS.items():
+        assert isinstance(val, str) and val.strip(), f"{key} is empty or non-string"
+
+def test_tooltips_values_are_short_enough_for_a_tooltip():
+    for key, val in zis_copy.TOOLTIPS.items():
+        assert len(val) <= 200, f"{key} is too long for a tooltip ({len(val)} chars)"