feat(kpi): expand KPI runtime monitoring, prompt advisory envelopes, and missing field resiliency

docs/INVITE-HANDLER.md

@@ -33,15 +33,30 @@ the agent browsers, exposed as `box invite` / `box usage`.
 - When account B redeems account A's code: BOTH accounts immediately
   receive 1 billion Muse tokens.
 
-## UI Quirks & Binary Attribution
+## UI Quirks & Missing Field Resiliency
 
 - **Redeem field disappearance**: In Settings > General, the `Redeem invite code`
   item is only present for fresh accounts (< 48 hours, has not redeemed). Once
   redeemed, the field disappears completely and is replaced by the `Additional tokens`
   ticker bar (`Never expires / X% used`).
-- **Asynchronous DOM Loading**: In the React/Radix UI tree, usage statistics and the
-  redeem button render asynchronously after the dialog opens. RPA drivers must poll
-  briefly for usage text and progress bars rather than evaluating on the first tick.
+- **Missing Entrypoint Recovery & API Fallback**:
+  If the `Redeem invite code` row is absent (or sub-dialog input box `NativeAuthCodeBoxes`
+  fails to mount):
+  1. Box polls up to 2.5s for React hydration.
+  2. If still unrendered, Box automatically falls back to in-page API redemption (`POST /api/hatch/invite-code/redeem`).
+  3. If API redemption succeeds, Box returns success transparently.
+  4. If API also fails, Box records the exact server reason (`already_redeemed`, `window_expired`, etc.).
+  5. Box cleanly dismisses all open modals via Escape to avoid orphaned UI state.
+- **Asynchronous DOM Loading & Unloaded Stats**:
+  In the React/Radix UI tree, usage statistics render asynchronously after the dialog opens.
+  If network requests stall or quota bars fail to render, `read_usage()` and `box usage` gracefully
+  tag the result as `UNLOADED` (`stats_loaded: false`) rather than throwing uncaught `RuntimeError`s.
+- **DM Loopback & Transparent Agent Feedback**:
+  To keep agents in the loop without causing confusion:
+  - Any missing expected field or failed redemption can trigger an automated loopback DM
+    via `box invite redeem <node> <code> --notify <sidechat> [--notify-agent <agent>]`.
+  - Onboard and salvage pipelines automatically post diagnostic notices (`[ONBOARD-SALVAGE-LOOPBACK]` /
+    `[BOX-INVITE-LOOPBACK]`) to the agent's task sidechat, providing clear, actionable root cause.
 
 ## Onboarding & Feeding Pipeline (`box onboard`)