[Feat/claude plugin] Add Claude Code plugin for log analysis

[hvsk004]

Add Claude Code plugin for log analysis

Description

Summary

Adds a Claude Code plugin for ctrlb-decompose, enabling users to analyze logs
directly from Claude Code by asking in plain language — no CLI knowledge required.

What's included

• plugin/ directory — self-contained Claude Code plugin with:
  • plugin.json — plugin metadata (name, version, license)
  • skills/analyze-logs/SKILL.md — skill that triggers on log analysis requests,
    handles installation of ctrlb-decompose across macOS/Linux/source, runs analysis
    with --llm --top 20, and interprets results (errors → anomalies → variable
    summaries → next steps)
  • README.md — plugin install/usage docs
• .claude-plugin/marketplace.json — marketplace listing so users can discover
  and install via /plugin marketplace add ctrlb-hq/ctrlb-decompose
• README update — added a "Claude Code Plugin" section with install and usage
  instructions

How it works

1. User asks Claude to analyze a log file or pastes log content
2. The analyze-logs skill triggers automatically
3. Checks if ctrlb-decompose is installed; walks through OS-appropriate
   installation if not (Homebrew, deb/rpm, binary, or build from source)
4. Runs ctrlb-decompose --llm --top 20 on the input
5. Interprets output — surfaces errors first, explains anomalies, summarizes
   variable patterns, and suggests next steps

Install

In Claude Code:
/plugin marketplace add ctrlb-hq/ctrlb-decompose
/plugin install ctrlb-decompose@ctrlb-hq