refactor(flake): consolidate palette imports through nomarchyLib

flake.nix was re-importing ./themes/palettes and recomputing
themeNames via builtins.attrNames in its outputs `let`, even though
lib/default.nix already exports both. Two evaluations of the same
data, same result today — drift risk tomorrow as soon as one
computation grows extra logic the other doesn't.

Added `nomarchyLib = import ./lib { inherit lib; }` once and reused
it via `inherit (nomarchyLib) themeNames;` for the allThemeVariants
linkFarm. The local `palettes` binding wasn't read by anything else in
the outputs so it goes away with the rewrite. lib/default.nix is now
the single source of truth for the theme list; modules under core/
and themes/engine/ already import ../../lib the same way and resolve
to the identical evaluation.

`nix flake check --no-build` clean.

docs/ROADMAP.md

@@ -38,7 +38,6 @@ Guardrails (apply when adding anything):
 - **Forgejo release pipeline.** `vYY.MM.x` tags matching the upstream NixOS channel; the pipeline pushes the three ISOs and an updated `flake.lock` snapshot.
 - **Optional `nomarchy-installer-vm`** rebuilt as a real flake app (not a one-off shell script) so users can install Nomarchy into a libvirt VM declaratively.
 - **Surface support module** via the relevant `nixos-hardware` profile + Surface kernel patches behind a `nomarchy.hardware.isSurface` toggle.
-- **Consolidate palette imports in `flake.nix` via `nomarchyLib`.** `flake.nix:79-80` re-imports `./themes/palettes` and recomputes `themeNames` even though `lib/default.nix` already exports both. Two computations, same result today — drift risk tomorrow. Import `nomarchyLib = import ./lib { inherit lib; }` once and use `nomarchyLib.{palettes,themeNames}` to make `lib/default.nix` the single source of truth for the theme list.
 - **Decide what to do about `features/apps/chromium/Default/Preferences`.** The module deploys a static 204-byte `Default/Preferences` (setting `extensions.theme.use_system = false`, `browser.theme.color_scheme = 2`) into chromium's mutable profile directory via Home Manager symlink. Chromium expects to write that file at runtime, so either the symlink is silently replaced on first save (losing the static defaults) or the write fails silently. The real chromium theming work happens via managed policies in `core/system/browser.nix`. Probably the user-profile deployment should be removed; needs someone with chromium-internals knowledge to confirm before deletion.
 - **`nomarchy-menu` "Setup → Config" pattern edits Nix-managed files.** Five of the nine entries in `show_setup_config_menu` open files that Home Manager generates from declarative options (`hypridle.conf` from `services.hypridle.settings`, `hyprsunset.conf` from `services.hyprsunset`, `walker/config.toml` from `programs.walker.config`, `waybar/config.jsonc` from `programs.waybar.settings`, `hyprland.conf` from `wayland.windowManager.hyprland.settings`). The menu pattern is "edit then restart", but a `home-manager switch` clobbers the edit and the file goes back to the Nix-generated content. Two more entries (`hyprlock.conf`, `swayosd/config.toml`) point at paths the modules don't deploy at all — `open_in_editor` creates an empty file. Either remove these entries (the user should edit the Nix module), or rewire each to open the matching Nomarchy option doc / module file path, or document the ephemerality in `notify-send` when entering edit mode. Picked up during Pillar 8 / Component 8.
 - **`themes/templates/*.tpl` — prune the truly dead, document the rest.** Eleven mustache-style templates deployed to `~/.local/share/nomarchy/templates/` via `themes/engine/files.nix`. Originally flagged as "no script consumes them" — that was wrong: `themes/engine/scripts/nomarchy-theme-set-templates` (called at the end of `nomarchy-theme-set`) reads them, substitutes palette colors, and writes the output to `~/.config/nomarchy/current/theme/<file>` only when no file is already there. Now categorise: **(a) functionally dead** — `alacritty.toml.tpl`, `btop.theme.tpl`, `chromium.theme.tpl`, `swayosd.css.tpl` all produce files at paths nothing reads (alacritty + swayosd are Stylix/Nix-themed; btop reads from `~/.config/btop/themes/nomarchy.theme` not from the theme symlink; chromium.theme references were deleted in `9b06b6c`). **(b) superseded** — `kitty.conf.tpl` and `ghostty.conf.tpl` are now generated by `themes/engine/files.nix` (commit `8d3ce2d`); the template path skips harmlessly via the "if not exists" check. **(c) still relevant** — `hyprland.conf.tpl`, `hyprlock.conf.tpl`, `obsidian.css.tpl`, `keyboard.rgb.tpl`, `hyprland-preview-share-picker.css.tpl` (this last one was orphaned when the share-picker dir was deleted in `20de3d4` — verify before keeping). Delete (a) + (b) + the orphan share-picker tpl; document the rest in `docs/creating-themes.md` as the layered override surface they actually are.
@@ -156,6 +155,7 @@ Pillar is **done** when every component has a closed `wave/qa-<component>` PR an
 
 (Move items here when they land — keep them brief, link the commit/PR.)
 
+- _2026-05-22_ — **`flake.nix` palette imports consolidated through `nomarchyLib`.** `flake.nix` was re-importing `./themes/palettes` and recomputing `themeNames` via `builtins.attrNames` even though `lib/default.nix` already exports both. Two evaluations of the same data set with the same result today — drift risk tomorrow. Added `nomarchyLib = import ./lib { inherit lib; }` once in the outputs `let` and reused it via `inherit (nomarchyLib) themeNames;` for the `allThemeVariants` linkFarm. `lib/default.nix` is now the single source of truth for the theme list — modules that need palette data import `../../lib` the same way and resolve to the same evaluation. `nix flake check --no-build` clean.
 - _2026-05-22_ — **`programs.uwsm` moved to `core/system/session.nix`.** The session-manager wiring (uwsm + the Hyprland Wayland-compositor entry that gives Hyprland a proper `graphical-session.target` so user services like `nomarchy-wallpaper`, walker and elephant chain off it) had lived in `core/system/virtualization.nix` by historical accident — loaded unconditionally on every install, nothing to do with libvirt/docker. Lifted into a dedicated `core/system/session.nix` and imported from `core/system/default.nix` between `systemd.nix` and `virtualization.nix`. `virtualization.nix` now contains only the libvirt + docker branches its filename implies. `nix flake check --no-build` clean. No behaviour change.
 - _2026-05-22_ — **`themes/templates/*.tpl` pruned.** Deleted 9 of the 11 mustache templates after verifying their output paths are either preempted by Nix-side writes (`hyprland.conf.tpl` shadowed by `themes/engine/files.nix:100`; `kitty.conf.tpl` + `ghostty.conf.tpl` shadowed by the per-palette generators added in commit `8d3ce2d`), unread by anything (`hyprlock.conf.tpl`, `alacritty.toml.tpl`, `btop.theme.tpl`, `chromium.theme.tpl`, `swayosd.css.tpl` — the corresponding apps are themed via Stylix / declarative Home-Manager options / the system policy module, not from the theme symlink), or orphaned (`hyprland-preview-share-picker.css.tpl` lost its consumer when the share-picker dir was deleted in `20de3d4`). Only `obsidian.css.tpl` (consumed by `nomarchy-theme-set-obsidian` to seed every Obsidian vault's theme) and `keyboard.rgb.tpl` (consumed by `nomarchy-theme-set-keyboard-asus-rog` to set the ROG keyboard tint) stay. Rewrote Step 6 of `docs/creating-themes.md` to describe the two remaining templates explicitly and corrected a long-standing path bug ("`~/.config/nomarchy/themed/`" → "`~/.config/nomarchy/themes/templates/`" — the script actually reads the latter). `nix flake check --no-build` clean.
 - _2026-05-22_ — **Pillar 4: "What's installed?" first-boot summary.** New `nomarchy-installed-summary` script renders a markdown table (via `gum format`, plain fallback) showing the install shape the user should verify before customising: theme / font / panel position (read from `~/.config/nomarchy/state.json`), timezone / DNS / hybrid-GPU (read from `/etc/nixos/state.json`), form factor (`BAT*` sysfs check — same signal the installer uses), software profiles (heuristic via presence of marker binaries: `docker` → Dev, `steam` → Gaming, `libreoffice` → Office, `obs` → Media, `rg` → CLI Utils), FDE status (any `crypt` entry in `lsblk`), and the drive layout (filtered `lsblk -no NAME,SIZE,TYPE,MOUNTPOINT`). `nomarchy-welcome` now calls it as Step 0 (gated on a `gum input` so the user acknowledges before customisation rewrites anything) and the same command works standalone from any terminal. No installer-side changes — the script is fully self-contained against existing state files and live introspection. Closes the "Installer: What's installed? summary on first boot" Now-column item.

flake.nix

@@ -38,6 +38,12 @@
     system = "x86_64-linux";
     lib = nixpkgs.lib;
 
+    # Shared Nomarchy helpers (palette loader, theme name list, wallpaper /
+    # icon-theme resolvers, base16 mapper). Importing here makes lib/default.nix
+    # the single source of truth — modules that need palette data import
+    # `../../lib` the same way and resolve to the same evaluation.
+    nomarchyLib = import ./lib { inherit lib; };
+
     # Overlays — the function form lives here so both Nomarchy itself and
     # any downstream flake (see `overlays.default` in the outputs) can layer
     # the same Nomarchy packages onto their nixpkgs.
@@ -76,8 +82,7 @@
     # pins `nomarchy.theme` (and clears the wallpaper override so the theme's
     # own default background is used) and exposes the generation's activation
     # package under its theme name.
-    palettes = import ./themes/palettes;
+    inherit (nomarchyLib) themeNames;
-    themeNames = builtins.attrNames palettes;
     themeVariantFor = themeName: (mkHome {
       username = "nomarchy";
       modules = [{