Package per-language codestyle sections as Skills

.agents/skills/shell-codestyle/SKILL.md

@@ -0,0 +1,55 @@
+---
+name: shell-codestyle
+description: >-
+  Governs Bash/shell script style for ptr727/ProjectTemplate fleet repos: when a bootstrap or
+  host-tool script may be shell instead of Python, the mandatory set -Eeuo pipefail header, the
+  pipefail-versus-early-reader pitfall, self-locating scripts, shellcheck cleanliness, and the
+  why-not-what comment rule. Use this whenever writing, reviewing, or editing a .sh file, whenever
+  deciding whether a new script should be Bash or Python, or whenever a pipeline built from
+  `curl`/`grep`/`jq`-style commands looks like it silently swallowed a failure. Triggers even when
+  the task looks like a one-line tweak to an existing script, because a missing `-e`/`pipefail`,
+  or a reader piped straight from a producer that closes the pipe early, are each invisible until
+  the exact failure mode they guard against actually happens. Fleet-wide: a shell script can
+  appear in any repo (a bootstrap that installs the interpreter, a host tool that must run before
+  a toolchain exists), not only a repo whose primary language is shell.
+---
+
+# Shell Codestyle
+
+## Why this exists
+
+This is the shell-specific half of the fleet's code style guide, kept in one place instead of
+re-derived per repo or per session. Shell is the fleet's exception language, reached for only
+where Python cannot run yet, so its rules exist to keep that narrow surface safe rather than to
+cover general scripting style.
+
+## When shell, not Python
+
+Bash, and only where a program cannot be Python: a bootstrap that installs the interpreter cannot
+be written in it, and a host tool that must run before a development toolchain exists cannot
+depend on one. Everything else is Python, with a test beside it.
+
+## Rules
+
+- **`set -Eeuo pipefail`, before the first command the script runs.** A header comment sits above
+  it, as `repo-config/configure.sh` and the `host-setup/` scripts do, since what matters is that
+  nothing executes unguarded rather than which line number it lands on. Without `-e` a failed
+  command in the middle of a sequence lets the rest run against a state nobody checked, and
+  without `pipefail` a pipeline reports the exit of its last stage, so a fetch that failed reads
+  as an answer when a parser downstream succeeds on an empty input. `-E` carries an `ERR` trap
+  into functions and command substitutions, so a script that later adds one is not surprised by
+  where it does not fire.
+- **A reader that stops early needs its producer read first.** Under `pipefail`, a producer
+  writing to a closed pipe exits non-zero, so `curl ... | grep -q` reports a successful fetch as
+  a failure whenever the match is found early enough. Capture the output, then search it.
+- **Self-locating, never dependent on the caller's directory.** A script resolves its own
+  directory from `BASH_SOURCE` and references its payloads through it, since the working
+  directory at invocation is not a property of the script.
+- **`shellcheck` clean, and a deliberate exception carries its reason inline.** A
+  `# shellcheck disable=SCxxxx` names why the rule does not apply here, so the next reader can
+  tell a considered exception from an unread warning. `repo-config/configure.sh` is the worked
+  example, carrying five `SC2016` disables where a single-quoted `jq` program must stay
+  unexpanded, each with its reason on the same line.
+- **Comments say why, never what.** The code states what it does. A comment restating it goes
+  stale silently, where a comment carrying a reason fails visibly when the reason stops being
+  true.

.claude-plugin/fleet-skills/.claude-plugin/plugin.json

@@ -9,8 +9,11 @@
     "./skills/carried-instruction-file-guard",
     "./skills/comment-and-doc-style",
     "./skills/copilot-instructions-keeper",
+    "./skills/dotnet-codestyle",
     "./skills/fleet-conformance-check",
     "./skills/pr-review-conduct",
-    "./skills/resync-a-repo"
+    "./skills/python-codestyle",
+    "./skills/resync-a-repo",
+    "./skills/shell-codestyle"
   ]
 }

.claude-plugin/fleet-skills/.source-digest

@@ -1 +1 @@
-5d298d74098bac47
+d2ea6560beea37fd