docs: update README with feature overview and module structure

Add Java extension support and configure multiple JDK runtimes.
Introduce a wrapped VS Code package that includes JDK 25 in the PATH
to support the Red Hat Java language server.

Switch from using `programs.vscode.userSettings` to a manually managed
`settings.json` file via `home.file`. This allows the settings file to
be writable by external tools like `kilo-code` at runtime while
preserving them across Nix configuration switches by using `force = false`.

docs/README.md

@@ -17,16 +17,26 @@ How to work on it: [conventions.md](./conventions.md).
 
 Each machine: `modules/hosts/<name>/default.nix` → `nixosConfigurations.<name>`, real config in `*Configuration` + optional `_private/` and `_services/`.
 
+## Features at a glance
+
+- **Users catalog** — one catalog in `modules/system/users.nix`, pick who exists on a host with `chiasson.users.enabled = [ "example" ]`, override per host. Home Manager wires itself from the same list.
+- **SSH + Bitwarden (rbw) keys** — one ed25519 keypair per catalog user, private key in Bitwarden, public key in `modules/ssh/inventory.nix`. Outbound SSH uses a `.pub` filter against the rbw agent; inbound `authorized_keys` are generated from the same inventory. [Full wiring in conventions.md](./conventions.md#ssh-model).
+- **Wisdom modules** — Home Manager slices in `modules/wisdom/` auto-catalog via `lib.wisdomCatalogExtraModules` (defined in `modules/desktop/options.nix`). The baseline `wisdom` module handles git identity + shared tools; all other `wisdom*` exports are pulled in once per user through `desktopHomeBase` → `chiasson.users.extraModules.olivier`. Hosts only flip `chiasson.home.<category>.<slice>.enable` — no manual imports in `home.nix`. Categories include `apps` (spotify, discord, localsend), `browsers` (chrome, edge, zen, …), `editors` (cursor, vscode, obsidian, …), `shells` (bash, fish, oh-my-posh, yazi), `desktop` (gtk-qt-theming, screenshot), and `terminals` (kitty). Trivial single-package slices can be written with the `lib.wisdomSlice` helper instead of repeating the `root`/`cfg` + `mkIf` boilerplate.
+- **Wallpapers from a dedicated repo** — `modules/desktop/wallpapers.nix` pins `inputs.wallpapers` into the store and exposes it as `CHIASSON_NIX_WALLPAPERS` and `/etc/wallpapers`. Override `chiasson.desktop.wallpapers.source` if needed.
+- **Private host data** — import-tree skips `_private/` globally, so machine-only files (firmware quirks, display configs, service tweaks) live next to the host module without leaking elsewhere.
+
 ## Deploy / rebuild
 
-Remote builds use the `builder` user (`systemDeployBuilder`, wired through `client-services` on desktops).
+Remote builds use the `builder` user (`systemDeployBuilder`, wired through `client-services` on desktops/laptops/tablets).
 
 Fleet deploy is [Navi](https://github.com/cafkafk/navi) — config in `modules/deploy/navi.nix`, outputs `flake.navi` / `flake.naviHive`.
 
 ```bash
-nix develop          # devShell has navi + hints
+nix develop          # devShell has navi + just + hints
+just                  # list local helpers like `sync-dms`
 navi apply --on <host>
 navi apply-local --node 14900k --sudo   # this machine, if hostname matches
+navi tui                  # interactive fleet dashboard
 ```
 
 Plain rebuild still works: `sudo nixos-rebuild switch --flake .#<host>`.
@@ -37,11 +47,11 @@ Plain rebuild still works: `sudo nixos-rebuild switch --flake .#<host>`.
 modules/
   hosts/<host>/     # per-machine composition
   system/           # nixosModules.system aggregate
-  desktop/          # GUI stack
+  desktop/          # GUI stack (niri, hyprland, plasma, DMS)
   wisdom/           # HM modules (exports still named wisdom*)
   ssh/              # inbound NixOS + outbound HM
   deploy/           # navi hive
-  lib/              # pure helpers → flake.lib
+  patches/          # one-off patches (yt-dlp, t2fanrd, …)
 ```
 
 Machine-only stuff lives in `hosts/<host>/_private/` — import-tree skips `_private/` globally, so those files only get pulled in where you import them.

modules/wisdom/editors/vscode.nix

@@ -12,8 +12,23 @@
         jnoortheen.nix-ide
         yzhang.markdown-all-in-one
         esbenp.prettier-vscode
+        vscjava.vscode-java-pack
+        redhat.java
       ];
 
+      # Wrap VS Code so a JDK is on PATH — the Red Hat Java language server (and
+      # other extension-bundled JVMs) need `java` to run, independent of the
+      # per-project `java.configuration.runtimes` setting.
+      vscodeWithJdk = pkgs.symlinkJoin {
+        name = "vscode-with-jdk";
+        paths = [ pkgs.vscode ];
+        nativeBuildInputs = [ pkgs.makeWrapper ];
+        postBuild = ''
+          wrapProgram "$out/bin/code" \
+            --prefix PATH : "${pkgs.jdk25}/bin"
+        '';
+      };
+
       coreSettings = {
         "nix.enableLanguageServer" = true;
         "nix.serverPath" = "nixd";
@@ -26,7 +41,26 @@
         };
         "diffEditor.ignoreTrimWhitespace" = false;
         "chat.disableAIFeatures" = true;
+
+        "java.configuration.runtimes" = [
+          {
+            name = "JavaSE-21";
+            path = "${pkgs.jdk21}/lib/openjdk";
+          }
+          {
+            name = "JavaSE-25";
+            path = "${pkgs.jdk25}/lib/openjdk";
+            default = true;
+          }
+        ];
       };
+
+      # Seed a *writable* settings.json (not a store symlink) so extensions like
+      # kilo-code can edit it at runtime. `force = false` in the config means HM
+      # only writes it when absent, preserving kilo's later edits across `switch`.
+      settingsJson = pkgs.writeText "vscode-user-settings" (
+        builtins.toJSON coreSettings
+      );
     in
     {
       options.chiasson.home.editors.vscode = {
@@ -48,13 +82,18 @@
       };
 
       config = lib.mkIf (root.enable && cfg.enable) {
-        home.packages = [ pkgs.vscode ];
+        home.packages = [ ];
+
+        # Writable, seed-once user settings (kilo-code can append to it).
+        home.file.".config/Code/User/settings.json" = {
+          source = settingsJson;
+          force = false;
+        };
 
         programs.vscode = {
           enable = true;
-          package = pkgs.vscode;
+          package = vscodeWithJdk;
           extensions = defaultExtensions ++ cfg.extensions;
-          userSettings = coreSettings;
         };
       };
     };