feat(410): the skills own the full reflexes, in words any client can read (#4029)

Step 2 of milestone 410 "One owner per piece of guidance". Skills are the
part of every client package shared verbatim (Agent Skills, decision #4027),
so they state each reflex in full and name no particular client.

using-scribe gains what only the static session context said:
- a retrieved rule outranks a default habit; ask when no rule speaks to it
- log on completing a task and on hitting a problem, not only successes
- the systems_hint on an untagged record is the tagging question, answered
  at the moment of work

Client-specific text leaves the skills, rewritten as the universal idea:
- using-scribe: "keep one copy" no longer names CLAUDE.md, MEMORY.md, native
  auto-memory or autoMemoryEnabled; "this plugin" becomes Scribe
- reusing-code / shape-accounting: Write/Edit and Bash become editor tools
  and shell edits; the prior-art "hook" becomes the prior-art hint; a plugin
  version number is dropped

tests/test_guidance_ownership.py:
- test_the_skills_name_no_particular_client fails on any Claude Code path,
  memory file, slash command, hook event or tool name in a skill, each
  marker commented with why it is client-specific; a companion test shows
  it can fail
- three registry topics for what using-scribe now owns; the loss guard
  stays green

Plugin version minted.

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

tests/test_guidance_ownership.py

@@ -112,6 +112,9 @@ TOPICS: tuple[Topic, ...] = (
     Topic("an id exists only once a create returns it", "skill:using-scribe",
           ("exists only once a create", "{{ref:")),
     Topic("tag records to systems as you write", "skill:using-scribe", ("system_ids", "create_system")),
+    Topic("answer the systems_hint at the moment of work", "skill:using-scribe", ("systems_hint",)),
+    Topic("a retrieved rule outranks a default habit", "skill:using-scribe", ("outranks a default habit",)),
+    Topic("log on completion and on a problem", "skill:using-scribe", ("hit or discover a problem",)),
     Topic("the project's design system binds ui", "skill:using-scribe", ("resolve_design_system",)),
     Topic("name the record, never just its number", "skill:using-scribe", ("name the record",)),
     Topic("project inception is a decision", "skill:using-scribe", ("decide_project_inception",)),
@@ -196,3 +199,55 @@ def test_the_loss_guard_can_fail():
     reported = missing_topics((split, absent, whole), surfaces)
     assert len(reported) == 2
     assert reported[0].startswith("'split'") and "nowhere" in reported[1]
+
+
+# ── The skills are client-neutral (milestone 410 step 2) ────────────────
+#
+# Agent Skills is an open format read by dozens of clients (#4023), so the
+# skills folder is the part of every client package that is shared verbatim.
+# Anything only one client understands belongs in that client's adapter —
+# for Claude Code, the plugin's static context, hooks and commands — or the
+# skill reads as nonsense everywhere else. Each marker below names a thing
+# exactly one client has:
+#   - "claude", "~/.claude", ".claude/"   the client itself and its paths
+#   - "claude.md", "memory.md", "auto-memory", "automemoryenabled"
+#                                          Claude Code's local memory files/setting
+#   - "/compact", "/scribe:"               Claude Code slash commands
+#   - "sessionstart", "userpromptsubmit", "pretooluse", "posttooluse"
+#                                          Claude Code hook event names
+#   - "write/edit"                         Claude Code's editor tool names
+#   - "claude_plugin_root"                 the Claude Code plugin root variable
+# `Bash` is matched case-sensitively as a word: it is Claude Code's shell tool
+# name, while "bash" in prose is just the shell.
+CLIENT_SPECIFIC = (
+    "claude", "~/.claude", ".claude/", "claude.md", "memory.md", "auto-memory",
+    "automemoryenabled", "/compact", "/scribe:", "sessionstart", "userpromptsubmit",
+    "pretooluse", "posttooluse", "write/edit", "claude_plugin_root",
+)
+CLIENT_TOOL_NAME = re.compile(r"\bBash\b")
+
+
+def client_specific_hits(text: str) -> list[str]:
+    hits = [m for m in CLIENT_SPECIFIC if m in text.lower()]
+    if CLIENT_TOOL_NAME.search(text):
+        hits.append("Bash")
+    return hits
+
+
+def test_the_skills_name_no_particular_client():
+    offenders = {
+        str(p.relative_to(ROOT)): client_specific_hits(p.read_text())
+        for p in sorted((ROOT / "plugin/skills").glob("*/SKILL.md"))
+    }
+    offenders = {path: hits for path, hits in offenders.items() if hits}
+    assert not offenders, (
+        f"skills that name one client: {offenders}. Skills are shared by every "
+        f"client package (decision #4027); say the universal thing in the skill "
+        f"and put the client's own name for it in that client's adapter."
+    )
+
+
+def test_the_client_guard_can_fail():
+    assert client_specific_hits("keep a copy in CLAUDE.md") == ["claude", "claude.md"]
+    assert client_specific_hits("edits made through Bash") == ["Bash"]
+    assert client_specific_hits("edits made through a bash shell") == []