zed: hide title bar sign-in, dock panels, switch icon theme

title_bar.show_sign_in disables the sign in button, which is shown by
default and serves no purpose without a Zed account.

Panel layout: project, outline, collaboration and git panels dock to
the right; the agent panel docks left.

Icon theme changed from Zed (Default) to Material Icon Theme. Note
this requires the Material Icon Theme extension to be installed;
Zed falls back to the default icons if it is absent, so a fresh
machine linking these dotfiles will not error.

home_config/zed/settings.json

@@ -7,6 +7,18 @@
 // custom settings, run `zed: open default settings` from the
 // command palette (cmd-shift-p / ctrl-shift-p)
 {
+  "project_panel": {
+    "dock": "right"
+  },
+  "outline_panel": {
+    "dock": "right"
+  },
+  "collaboration_panel": {
+    "dock": "right"
+  },
+  "git_panel": {
+    "dock": "right"
+  },
   "edit_predictions": {
     "allow_data_collection": "no",
     "provider": "open_ai_compatible_api",
@@ -19,6 +31,10 @@
   },
   "disable_ai": false,
   "agent": {
+    "dock": "left",
+    "profiles": {
+      
+    },
     "default_model": {
       "provider": "PFI-LiteLLM",
       "model": "gen"
@@ -61,7 +77,10 @@
     }
   },
   "vim_mode": false,
-  "icon_theme": "Zed (Default)",
+  "title_bar": {
+    "show_sign_in": false
+  },
+  "icon_theme": "Material Icon Theme",
   "ui_font_size": 16.0,
   "buffer_font_size": 15,
   "theme": {