add an empty zshrc template for the owner

Somewhere to put what the owner actually wants, to be filled in and wired up
tomorrow. Not referenced by the Shell section yet.

The header records the decision that has to be made when it is: the section does
not install a .zshrc today, it appends four marker-wrapped blocks — starship,
agent, aliases, editor — through append_once. A template that is installed AND
appended to ends up with the same lines twice, so those blocks either move into
this file or stay out of it, not both.

zshrc, no leading dot: a template in a repository, not a dotfile in a home
directory, matching tmux.conf beside it and src/servers/shell-skel/zshrc which
has been spelled that way all along.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/setup/machine-setup/zshrc

@@ -0,0 +1,34 @@
+# Officer — the owner's shell configuration.
+#
+# EMPTY ON PURPOSE, for now. Created 2026-08-13 so there is somewhere to put the
+# things the owner actually wants, and it is not wired into the Shell section yet.
+#
+# ── What this replaces, and the decision still to make ──
+#
+# The Shell section does not install a .zshrc today. It APPENDS four
+# marker-wrapped blocks to whatever is already there — `starship`, `agent`,
+# `aliases` and `editor` — via `append_once`, which recognises its own work so a
+# second run does not duplicate it. That was the right call for a machine whose
+# .zshrc already belongs to somebody.
+#
+# Installing a whole file is a different promise, and the two do not compose: a
+# template that gets installed AND appended to ends up with the same lines twice,
+# once from the file and once from a block. So when this is wired in, the four
+# append_once blocks either move INTO this file or stay out of it — not both.
+#
+# `install_config` already handles the careful half: it writes only when the
+# destination is missing or still byte-for-byte the template, and offers a diff
+# otherwise, so an owner's own edits are never overwritten.
+#
+# ── Naming ──
+#
+# `zshrc`, no leading dot. It is a template in a repository, not a dotfile in a
+# home directory — the same reason tmux.conf lost its dot beside it. The member
+# equivalent, src/servers/shell-skel/zshrc, has been spelled that way all along.
+#
+# ── The one thing worth keeping when this is filled in ──
+#
+# shell-skel/zshrc depends on nothing but zsh: starship, eza, nvim and bun are
+# each used only if present, so the same file works on a minimal VPS and on a
+# fully equipped workstation. Worth holding to here, since this file will be read
+# on machines that have had none of the optional sections run.