Add more community packs

[sampleXbro]

What problem does this solve?

agentsmesh install <source> already supports installing canonical resources (rules, commands, agents, skills, MCP, hooks, ignore, permissions) from any git repo, but discoverability is low: there is no curated list of community packs that new users can install in one command to get value immediately.

This is a chicken-and-egg problem at launch — without a few visible packs, users don't realize how easy it is to share config; without sharing being easy, packs don't get published.

Proposed solution

Seed an initial set of community packs and document them on the website:

1. A small "house style" pack (TypeScript/React/Node) with rules and a couple of slash commands.
2. A "security review" pack with lint-style rules and an agents/code-security-auditor.md.
3. A "release manager" pack with a skills/release-manager/SKILL.md.

Then add a Community packs page to the docs that:

• Lists each pack with the install command (agentsmesh install github:org/pack@version).
• Explains how to publish a new pack and submit it to the list (PR-based for now).
• Links to the install/extends docs.

Each seeded pack can live in a dedicated repo under the agentsmesh-packs/ org or as subdirectories of a single agentsmesh-packs monorepo, whichever is easier to maintain.

Acceptance criteria

• At least four community packs are published (in this org or contributor-owned repos) and can be installed via agentsmesh install.
• Each pack has its own README.md explaining what it provides and which targets it works with.
• Docs page community/packs lists every pack with copyable install commands.
• Submission process for new packs is documented (PR template, naming, versioning).
• Packs install cleanly with --dry-run and produce diffs that match expectations.

Alternatives considered

No response