Scaffold the dsh-slopo bundle and port slopo's three agent skills

The three SKILL.md files are ports of the configs slopo 0.8.0 ships for
Claude Code, not new prose. What changed is the mechanics:

  * name + description frontmatter, both required by dsh
  * disable-model-invocation: true kept verbatim -- dsh has the same key,
    and slopo makes that choice for a reason (every one of these commands
    can spend minutes embedding)
  * allowed-tools / argument-hint / arguments dropped, not dsh keys
  * the !`slopo ...` shell-injection directive replaced with an
    instruction to call the slopo tool plus an explicit failure check,
    because dsh skill bodies do not execute commands

The guidance prose is quoted from slopo; NOTICE.md records the mapping and
the licence obligation that follows from it (AGPL-3.0-or-later, matching
upstream and the LICENSE file fetched from it).

skills/slopo-analyze-ignore/SKILL.md

@@ -0,0 +1,38 @@
+---
+name: slopo-analyze-ignore
+description: Slopo reports similar code across the whole codebase and this skill triages the obvious false positives into the ignore file. Use for a first pass over a codebase's duplicate clusters.
+disable-model-invocation: true
+---
+
+# Initialization
+
+1. Call the `slopo` tool with `action: "analyze"`.
+   - The tool may answer that it started a background job. Wait for that job and read its output before continuing — the report is that output.
+2. If the call failed, report the error message and stop.
+
+# Report structure
+
+The report contains either:
+- a list of clusters with file paths and line ranges, or
+- the message "No duplicates found".
+
+If there are clusters to analyse:
+- the first line contains the path to the ignore file;
+- each cluster has a header line with a number and a hash, in the form `cluster N (hash):`.
+
+Similar code was detected using embedding models, so many results are likely similar by coincidence.
+
+# Instructions
+
+Your task is to take a quick look at each cluster and mark as ignored the ones containing code that is not a duplication worth taking action on. An ignored cluster contains duplication obviously not worth taking action on, or it is similar by coincidence. If justifying a keep or an ignore takes more than a short phrase, it is not obvious.
+
+For every ignored cluster, insert its hash into the ignore file. One hash per line. Inline comments are allowed, for example `78a8d42e60e8 # your short note`.
+
+This work is a quick check, not deep analysis. Decide each cluster from a single look. The report size should not change how you judge one cluster. A report with a few tens of clusters is not a reason to dig deeper. A report with a few hundred is not a reason to rush.
+
+Rules:
+- Load only the line ranges specified in the report. Do not read surrounding code or callers.
+- Ignore only obvious false positives, when a quick check is enough to decide. When unsure, keep the cluster.
+- If only part of the cluster is worth keeping, keep the whole cluster.
+
+Process clusters in batches; do not load everything at once.