refactor: nix/host-modules + nix/agent-modules layout, update doc paths

CLAUDE.md

@@ -63,12 +63,16 @@ hand-maintained per-file tree drifts out of sync with the code.
 ### Other top-level dirs
 
 - **`frontend/`** — npm workspaces → static dashboard + per-agent UI
-  dist, built hermetically by `nix/frontend.nix`. Packages: `shared`
-  (terminal pane + Catppuccin palette), `dashboard` (the operator SPA),
-  `agent` (the default per-container UI).
-- **`nix/`** — NixOS modules (`modules/hive-{c0re,forge,gateway,matrix,
-  ci,network}.nix`) + per-container templates (`templates/{harness-base,
-  agent-base,manager,weston-vnc}.nix`) + the options-doc derivation.
+  dist, built hermetically by `nix/packages/frontend.nix`. Packages:
+  `shared` (terminal pane + Catppuccin palette), `dashboard` (the
+  operator SPA), `agent` (the default per-container UI).
+- **`nix/`** — `host-modules/` (the host stack: hyperhive core options,
+  `hive-{c0re,priv,forge,gateway,matrix,network,tls,ci}`, otel, swarm),
+  `agent-modules/` (the per-agent harness feature modules),
+  `templates/{agent,ruth}.nix` (container entry points), `packages/`
+  (flake package outputs), `docs/` (the options-doc derivation), plus
+  `sources.nix` / `rust.nix` / `checks.nix` / `devshell.nix` /
+  `treefmt.nix` behind the thin `flake.nix`.
 - **`docs/`** — subsystem reference docs (see *Reading paths* below).
 - **`branding/`**, **`scripts/`** — static assets + helper scripts.