feat(FN-3007): merge fusion/fn-3007

Commits merged:
- feat(FN-3007): complete Step 4 — document system memory usage bar
- fix(FN-3007): restore custom provider mapper type compatibility
- test(FN-3007): complete Step 2 — cover memory bar semantics and severity
- feat(FN-3007): complete Step 1 — add semantic memory usage progressbar
- test(FN-3007): complete Step 2 — cover memory usage progress semantics
- feat(FN-3007): complete Step 1 — add system memory usage bar

Files changed:
docs/architecture.md                               |  2 +-
 .../app/components/ModelOnboardingModal.tsx        | 27 ++++++------
 .../dashboard/app/components/SettingsModal.tsx     | 27 ++++++------
 .../dashboard/app/components/SystemStatsModal.css  | 48 ++++++++++++++++++++++
 .../dashboard/app/components/SystemStatsModal.tsx  | 29 +++++++++++--
 .../components/__tests__/SystemStatsModal.test.tsx | 33 +++++++++++++++
 6 files changed, 133 insertions(+), 33 deletions(-)

Fusion-Task-Id: FN-3007

packages/dashboard/app/components/SystemStatsModal.css

@@ -113,6 +113,54 @@
   gap: var(--space-md);
 }
 
+.system-stats-modal__row--memory-used {
+  align-items: stretch;
+  flex-direction: column;
+}
+
+.system-stats-modal__row--memory-used dd {
+  width: 100%;
+  justify-content: flex-end;
+}
+
+.system-stats-modal__memory-progress-wrapper {
+  width: 100%;
+}
+
+.system-stats-modal__memory-progress-track {
+  width: 100%;
+  height: var(--space-sm);
+  border-radius: var(--radius-sm);
+  background: var(--border);
+  overflow: hidden;
+}
+
+.system-stats-modal__memory-progress-track--warning {
+  box-shadow: inset 0 0 0 var(--btn-border-width) var(--color-warning);
+}
+
+.system-stats-modal__memory-progress-track--critical {
+  box-shadow: inset 0 0 0 var(--btn-border-width) var(--color-error);
+}
+
+.system-stats-modal__memory-progress-fill {
+  height: 100%;
+  border-radius: var(--radius-sm);
+  transition: width var(--transition-normal), background-color var(--transition-normal);
+}
+
+.system-stats-modal__memory-progress-fill--normal {
+  background: var(--color-success);
+}
+
+.system-stats-modal__memory-progress-fill--warning {
+  background: var(--color-warning);
+}
+
+.system-stats-modal__memory-progress-fill--critical {
+  background: var(--color-error);
+}
+
 .system-stats-modal__row dt {
   margin: 0;
   font-size: 0.85rem;