model: add onSuccess/onFailure lifecycle hooks to modelRegister

docs/hoover.md

@@ -144,6 +144,8 @@ modelRegister('firewall', {
         return r.data;
     },
     defaultData: null,               // optional, initial data value
+    // onSuccess: (name, data, param?) => { },  // optional — after model.data is set (also for null)
+    // onFailure: (name, error) => { },         // optional — after model.error is set (real throws only)
 });
 
 // Parameterized example — tab-aware fetch:
@@ -164,6 +166,8 @@ modelRegister('logs', {
 | `definition.subsystem` | WS topic string. Use `'firewall'`, `'dnsmasq'`, etc. Use `'*'` to match all topics. |
 | `definition.fetch(signal?, param?)` | Async function that fetches and returns data. Throws on error. Receives optional `AbortSignal` and optional parameter (e.g., tab key). |
 | `definition.defaultData` | Optional initial data value (default: `null`) |
+| `definition.onSuccess(name, data, param?)` | Optional lifecycle hook called after `model.data` is assigned — including `data === null` (a resolved `null` is normal, not an error). `param` is the action object passed to `fetch` (or `undefined`), so hooks can tell which action produced the data. Fire-and-forget: hook errors are caught and logged via `console.warn`; they never clobber `model.error`, the returned promise, or the `finally` flag clearing. |
+| `definition.onFailure(name, error)` | Optional lifecycle hook called after `model.error` is assigned. Only reachable on a real throw from `fetch` (e.g., network error). Same fire-and-forget error isolation as `onSuccess`. |
 
 ### `getModel(name)`
 
@@ -212,7 +216,7 @@ modelFetch('logs', 'nginx-access');
 - On failure, stores error in `model.error`.
 - Flags cleared in `finally` block.
 - Does not abort in-progress fetches — other consumers may still need the data.
-- The `param` argument is passed to `fetch(signal, param)` for parameterized models. Dedup key is `name: param`.
+- The `param` argument is passed to `fetch(signal, param)` for parameterized models. Dedup key is `name` (no param) or `name: JSON.stringify(param)` (with param) — object params (e.g. `{ action: 'refresh' }` vs `{ action: 'check' }`) therefore get distinct keys, and param-less `modelFetch(name)` calls retain the bare `name` key.
 
 ### `refreshByTopic(topic)`