fix(gui): Final Phase 7 stabilization and polish

- Resolve ImportError by correctly prefixing 'src' in modular renderers.
- Fix ImGui access violation by ensuring push_id always receives string IDs.
- Restore visible role-based background tints using layered rendering (channels).
- Definitively fix horizontal Markdown table widths by forcing group expansion.
- Centralize color management in theme_2.py and ui_shared.py.
- Standardize Files & Media inventory layout and remove legacy controls.
- Update test mocks to support modular UI and theme-driven styling.

src/theme_2.py

@@ -420,10 +420,11 @@ def ai_text_style():
 
 def get_role_tint(role: str) -> imgui.ImVec4:
  """Returns a subtle background tint color based on the message role."""
- if   role == "User":       return imgui.ImVec4(30/255, 40/255, 60/255, 0.5)
- elif role == "AI":         return imgui.ImVec4(35/255, 55/255, 45/255, 0.5)
- elif role == "Vendor API": return imgui.ImVec4(55/255, 45/255, 30/255, 0.5)
- return imgui.ImVec4(25/255, 25/255, 25/255, 0.4)
+ # Slightly more opaque and distinct tints for role-based structure
+ if   role == "User":       return imgui.ImVec4(0.12, 0.18, 0.30, 0.6) # Deep Blue
+ elif role == "AI":         return imgui.ImVec4(0.14, 0.25, 0.18, 0.6) # Deep Green
+ elif role == "Vendor API": return imgui.ImVec4(0.25, 0.22, 0.12, 0.5) # Earthy Gold
+ return imgui.ImVec4(0.1, 0.1, 0.1, 0.4) # Dim System
 
 def render_post_fx(width: float, height: float, ai_status: str, crt_enabled: bool) -> None:
  """Updates and renders the alert and CRT filters."""