feat(chat): reach Sessions from the chat tab

v1.1.0 moved the chat out of the right-hand container and left Sessions there alone. That
container is one VS Code hides by default, and `AI: Sessions` had no icon, no keybinding
and no button anywhere — so the only route from a conversation to your own past
conversations was knowing the palette entry existed.

It joins the three actions already on the chat tab, between New Chat and Set API Key:
per-conversation actions first, then "go somewhere else", then settings.

  navigation@0  Add Files      $(new-file)
  navigation@1  New Chat       $(add)
  navigation@2  Sessions       $(history)   <- new
  navigation@3  Set API Key    $(key)

The command also gains an icon. It never had one, because until now it was only ever
invoked from the palette — and an editor/title action without an icon renders as literally
nothing, a bug the suite already pins for the other three.

No new keybinding: ⇧⌘I already opens the chat, and a second shortcut for a one-click button
is a conflict looking for somewhere to happen.

Guards, each bypass-verified by reverting the fix:
  - the button removed from the tab
  - the icon dropped, so the action renders as nothing
  - moved out of the navigation group, where it would only ever appear under the … overflow

23 tests in chatSurface, 34 suites green.

Author: ndemianc

extensions/levelcode-ai/package.json

@@ -133,7 +133,8 @@
       {
         "command": "levelcode.ai.sessions",
         "title": "AI: Sessions",
-        "category": "LevelCode"
+        "category": "LevelCode",
+        "icon": "$(history)"
       },
       {
         "command": "levelcode.ai.sketch",
@@ -218,10 +219,15 @@
           "group": "navigation@1"
         },
         {
-          "command": "levelcode.ai.setApiKey",
+          "command": "levelcode.ai.sessions",
           "when": "activeWebviewPanelId == 'levelcode.ai.chat'",
           "group": "navigation@2"
         },
+        {
+          "command": "levelcode.ai.setApiKey",
+          "when": "activeWebviewPanelId == 'levelcode.ai.chat'",
+          "group": "navigation@3"
+        },
         {
           "command": "levelcode.ai.review.keepActive",
           "when": "levelcode.ai.reviewActive",

extensions/levelcode-ai/test/chatSurface.test.js

@@ -189,7 +189,11 @@ test('COMMAND: the chat TAB carries the actions the view title used to', () => {
 	const onTab = (pkg.contributes.menus['editor/title'] || [])
 		.filter((m) => m.when === "activeWebviewPanelId == 'levelcode.ai.chat'");
 	const ids = onTab.map((m) => m.command);
-	for (const id of ['levelcode.ai.newChat', 'levelcode.ai.addFileContext', 'levelcode.ai.setApiKey']) {
+	// Sessions joined them: with the chat out of the right-hand bar, its container is one VS Code
+	// hides by default, and `AI: Sessions` had no icon, no keybinding and no button anywhere — so the
+	// only route to your own past conversations was knowing the palette entry existed.
+	for (const id of ['levelcode.ai.newChat', 'levelcode.ai.addFileContext', 'levelcode.ai.setApiKey',
+		'levelcode.ai.sessions']) {
 		assert.ok(ids.includes(id), id + ' lost its button when the sidebar view was removed');
 		const cmd = pkg.contributes.commands.find((c) => c.command === id);
 		assert.ok(cmd && cmd.icon, id + ' has no icon — an editor/title action with no icon renders as nothing');
@@ -199,6 +203,11 @@ test('COMMAND: the chat TAB carries the actions the view title used to', () => {
 			m.command + ' must be in navigation, so VS Code can overflow it into … on a narrow tab');
 	}
 
+	// The one thing still living in the right-hand container must stay reachable FROM the chat, or it
+	// is reachable only by knowing it is there.
+	assert.ok(ids.includes('levelcode.ai.sessions'),
+		'no way from the conversation to the list of past conversations except the command palette');
+
 	// And nothing may be scoped to the view that no longer exists — a stale `when` is a button that
 	// never appears anywhere.
 	const all = Object.values(pkg.contributes.menus).flat();