Add global keyboard EventRouter and unify publish (M6, §01D)

One module owns the document keydown listener and dispatches the shortcut map
(Cmd/Ctrl+Shift+N / +K / +S / +, / Escape), platform-aware, via the single-source
focus-utils interactive-context gate. Escape and Cmd/Ctrl+S run before the gate so
save works while editing; the rest are suppressed mid-typing. Publish + its toast
move into services/snippet-actions so the button and Cmd/Ctrl+S behave identically.
Removes the ad-hoc keydown handler from App and Monaco's Cmd+S command.

docs/architecture/04-routing-and-events.md

@@ -320,7 +320,17 @@ function onKeyDown(e: KeyboardEvent): void {
 
   const mod = isMac ? e.metaKey : e.ctrlKey;
 
-  // --- Shortcuts: never fire while typing in an input or Monaco ----------
+  // Cmd/Ctrl + S -> publish current draft. Checked BEFORE the interactive-context
+  // gate: it is the canonical "save" shortcut (spec §01D mandates it override the
+  // browser default), and publishing happens *while editing the draft in Monaco* —
+  // gating it behind "not typing" would defeat its purpose.
+  if (mod && !e.shiftKey && e.key.toLowerCase() === 's') {
+    e.preventDefault(); // override the browser "save page" dialog
+    useSnippetStore.getState().publishDraft();
+    return;
+  }
+
+  // --- Remaining shortcuts: never fire while typing in an input or Monaco ----
   if (isInInteractiveContext()) return;
 
   // Cmd/Ctrl + Shift + N -> new snippet
@@ -336,16 +346,12 @@ function onKeyDown(e: KeyboardEvent): void {
     toggleDatasets();
     return;
   }
-  // Cmd/Ctrl + S -> publish current draft
-  if (mod && e.key.toLowerCase() === 's') {
-    e.preventDefault(); // override the browser "save page" dialog
-    useSnippetStore.getState().publishDraft();
-    return;
-  }
-  // Cmd/Ctrl + , -> settings (through the coordinator: snapshot + URL sync)
+  // Cmd/Ctrl + , -> open the editor settings popover. Settings are distributed to
+  // per-pane disclosure popovers, not a modal (spec §07), so this opens the editor
+  // cluster (openSettingsPopover) — there is no 'settings' modal to open.
   if (mod && e.key === ',') {
     e.preventDefault();
-    openModal('settings');
+    openSettingsPopover('editor-settings');
     return;
   }
 }
@@ -392,9 +398,13 @@ by inserting a rung at the right priority — never by sprinkling
 `e.preventDefault()` so Cmd/Ctrl+S does not trigger "save page", Cmd/Ctrl+K
 does not focus the browser search bar, etc.
 
-Note the asymmetry: **Escape is checked before the interactive-context gate**
-(you want Escape to dismiss a modal even while focus is in the editor), whereas
-all other shortcuts are checked **after** the gate (so they don't fire mid-typing).
+Note the asymmetry: **Escape and Cmd/Ctrl+S are checked before the
+interactive-context gate.** Escape, so it dismisses a modal even while focus is in
+the editor; Cmd/Ctrl+S, because publishing the draft is something you do _while_
+editing it — gating "save" behind "not typing" would defeat it (and it must
+override the browser's "save page" regardless). The remaining shortcuts (new
+snippet, toggle Datasets, settings) are checked **after** the gate, so they never
+fire mid-typing or steal a key the editor wants (e.g. Monaco's own Cmd+K chord).
 
 ### 2.2 The single-source helper: `orchestration/focus-utils.ts`
 

docs/architecture/10-interaction-and-feedback.md

@@ -65,6 +65,13 @@ nature of the message, not by convenience.
   _inline on the control_ ("Copied") with a polite `aria-live` announcement for assistive
   tech, never a toast-per-copy. This refines the spec's earlier blanket "every action
   toasts" (spec §01F/§02/§05, reconciled).
+- **An action's confirmation belongs with the action, not its call site.** When an action is
+  reachable from more than one trigger (e.g. publish is both a toolbar button _and_
+  Cmd/Ctrl+S), pair the store mutation and its toast in **one `services/` helper**
+  (`publishActiveSnippet`) that every trigger calls — otherwise the toast rides one path and
+  the other publishes silently (the exact inconsistency this rule prevents). The shortcut is
+  owned globally by the EventRouter (arch 04), so the helper is the only place the outcome is
+  confirmed.
 - **The same failure can light up two channels.** An unrenderable spec shows the _same_
   message inline in both the editor (§03E) and the preview (§04) — one producer
   (`PreviewStore`), two subscribers. That's intentional, not duplication.