feat(ops-hub): add Vendor State tab with quota + context + cache

- New module-level render_vendor_state(app) in gui_2.py
- New 'Vendor State' tab in render_operations_hub tab_bar
- Renders 5 stable metrics: provider_model, context_window, cache, quota, last_error
- Each row: Metric label | Value | State (colored ok/warn/error/info)
- Tooltips via imgui.set_tooltip on the value cell

ImGui scope linter: render_vendor_state OK. Pre-existing 2 errors at lines
2684 and 4994 unrelated to this commit.

src/gui_2.py

@@ -4028,6 +4028,30 @@ def render_operations_hub(app: App) -> None:
       curr = app.controller.ui_tier_layout_bindings.get(t, ""); idx = profiles.index(curr) if curr in profiles else 0
       ch_combo, new_idx = imgui.combo(t, idx, profiles)
       if ch_combo: app.controller.ui_tier_layout_bindings[t] = profiles[new_idx]
+  with imscope.tab_item("Vendor State") as (exp, _):
+   if exp: render_vendor_state(app)
+
+def render_vendor_state(app: App) -> None:
+ """Render the Operations Hub > Vendor State panel.
+ [C: src/vendor_state.py:get_vendor_state]
+ """
+ from src.vendor_state import get_vendor_state
+ metrics = get_vendor_state(app)
+ if imgui.begin_table("vendor_state", 3, imgui.TableFlags_.row_bg | imgui.TableFlags_.borders):
+  imgui.table_setup_column("Metric", imgui.TableColumnFlags_.width_fixed, 180)
+  imgui.table_setup_column("Value", imgui.TableColumnFlags_.width_stretch)
+  imgui.table_setup_column("State", imgui.TableColumnFlags_.width_fixed, 60)
+  imgui.table_headers_row()
+  state_colors = {"ok": vec4(120, 220, 120), "warn": vec4(240, 200, 80), "error": vec4(240, 80, 80), "info": vec4(180, 180, 180)}
+  for m in metrics:
+   imgui.table_next_row()
+   imgui.table_next_column(); imgui.text(m.label)
+   imgui.table_next_column()
+   imgui.text(m.value)
+   if imgui.is_item_hovered(): imgui.set_tooltip(m.tooltip)
+   imgui.table_next_column()
+   imgui.text_colored(state_colors.get(m.state, vec4(180, 180, 180)), m.state)
+  imgui.end_table()
 
 def render_message_panel(app: App) -> None:
  if app.perf_profiling_enabled: app.perf_monitor.start_component("_render_message_panel")