hub v0.42.0: remote "Debug mód" toggle on the customer config editor

Adds a form-level debug-mode checkbox to the customer config editor so an
operator can flip the controller's Logging.Level=debug (/debug menu + verbose
log) remotely, without SSH. Form field (not raw-JSON injection) because
handleConfigUpdate rebuilds ConfigJSON from the form on every save; the
config-version bump makes the controller re-pull + self-restart next cycle.

- buildConfigJSON: debug_mode checked -> "logging":{"level":"debug"};
  unchecked -> logging key omitted.
- config_form.html: "Hibakeresési mód (fejlesztői)" section + render state.
- configs_debug_test.go: form->JSON both ways; full-path survival test
  (debug lands, offsite descriptor unchanged, foreign-key red-proof); render
  state; red-proof exercised.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

hub/CHANGELOG.md

@@ -1,5 +1,28 @@
 # Felhom Hub — Changelog
 
+## v0.42.0 — Remote "Debug mód" toggle on the customer config editor (2026-07-10)
+
+Lets an operator flip the controller's debug mode (verbose log + the `/debug` menu, which the controller
+gates on `Logging.Level=="debug"` / `isDebug()`) **remotely, without SSH** — the support workflow (today:
+Peti's box). The config-version bump on save makes the controller re-pull + self-restart on its next
+report ACK, so the switch takes effect within a cycle, hands-free.
+
+- **Form field, not raw-JSON injection — on purpose.** `handleConfigUpdate` REBUILDS `ConfigJSON` from the
+  form on every save (`buildConfigJSON`), so any foreign key injected straight into the stored JSON is
+  dropped on the next save. The toggle is therefore a real form field, which by definition survives every
+  save. (The offsite descriptor survives via its own separate provision-merge, untouched by this.)
+- **`buildConfigJSON`** (`internal/web/configs.go`): `debug_mode` checked → emits `"logging":{"level":"debug"}`;
+  unchecked → the `logging` key is OMITTED entirely (the generated `controller.yaml` default stands — no
+  needless `"info"`).
+- **Config form** (`templates/config_form.html`): new collapsible **"Hibakeresési mód (fejlesztői)"** section
+  with the `debug_mode` checkbox; render state parsed back from `ConfigJSON` (`logging.level=="debug"` → checked).
+  No change to the offsite/CF/git leg; no generic raw-JSON editor (deliberately — validated surfaces only).
+- **Tests (non-hollow, `configs_debug_test.go`):** form→JSON both ways (checked emits / unchecked omits);
+  full-path **survival test** through `handleConfigUpdate` proving the debug key lands, the offsite descriptor
+  is byte-for-byte unchanged across save+re-provision, and the **red-proof** that a hand-injected foreign key
+  is gone after one save (why the switch must be a form field); render state both ways. Red-proof exercised
+  (feature disabled → survival + form tests fail).
+
 ## v0.41.0 — SLICE 4: OffsiteChecker (fill + staleness) + operator freeze lever (2026-07-09)
 
 The last build item of the offsite arc (pairs with controller v0.109.0's soft-quota gate + report object).