Research 018 graduates: ADRs 0173–0177 and to-be 37, the operator's machine

Every configurable thing on a node is a module, the home included, and a
module is whatever it declares (0173, extending 0040). A node varies a module
only through a setting rendered into the file or a kept region, never an edit
(0174, extending 0011; issue 168 first). One tool runtime per node serves every
module's tools on the host side, never in a container; the console is its
serving mode, renamed node-tools (0175, extending 0150; 0047/0150/0152 carry
dated notes). The login shell is a node seat held by one shell module with
`execute` as its contract (0176). A unit may be user-scoped and the service
manager is a node seat held by systemd (0177).

To-be 37 is handed off in-progress to mesh-host, mesh-controller, mesh-tools
and mesh-catalog, with the build in order: the account on every node, the
runtime, zsh, systemd, then the graphical stack. To-be 29 keeps ~/.ssh and
points at 37; 33 §6 and 34 are amended; the glossary gains node tools, bundle,
kept region, installed/holding, and retires flavor.

02-DECISIONS/0040-what-a-module-is.md

@@ -78,6 +78,8 @@ capability. The host hardcodes no firewall, supervisor, package manager or runti
 generic apply primitives and platform detection, so it runs where none of those exist — an Android
 phone has no ufw, systemd, pacman or Docker.
 
+> **The mechanism changed — 2026-10-02, by [ADR 0176](0176-the-login-shell-is-a-node-seat-and-execute-is-its-contract.md).** The shell example above — *bash, zsh and fish all join `shell`; one may be default* — is read as *installed is not holding*: the three may all be installed, and the `login-shell` seat is node-scoped and held by exactly one. The decision — what a module is, and the three relationships — stands; [ADR 0173](0173-the-operators-machine-is-the-meshs-and-a-module-is-what-it-declares.md) applies it to the operator's whole machine.
+
 ## Consequences
 
 - **Supersedes the earlier "grouped by domain" decision** (folded in consolidation; see the