feat: v7.0.0 — 6 new engineering skills, badges, milestone tracker, SKILL_REQUEST.md

New skills added to pm-engineering bundle (now 10 skills total):
- debugging-log-analyser: stack trace → structured root cause diagnosis + fix
- pr-description-writer: diff/commits → reviewer-ready PR description
- system-design-interview: full system design with capacity, components, trade-offs
- changelog-generator: git log → polished Keep a Changelog entry
- test-strategy-doc: spec/PRD → complete test strategy with P0/P1 test cases
- runbook-writer: operational runbooks with exact commands, rollback, and escalation

README updates:
- 5 shields.io badges (stars, skill count, version, install, license)
- "See It in Action" demo section
- pm-engineering added to Quick Install list
- Star Milestone Tracker (100/250/500/1000 stars roadmap)
- Engineering table extended from 4 to 10 skills (41–50)
- Article 14 link resolved from remote merge

Config updates:
- marketplace.json: v6.0.0 → v7.0.0, "106 skills"
- pm-engineering plugin.json: v1.0.0 → v2.0.0

New file: SKILL_REQUEST.md — community skill voting board

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/pm-engineering/.claude-plugin/plugin.json

@@ -1,13 +1,13 @@
 {
   "$schema": "https://anthropic.com/claude-code/plugin.schema.json",
   "name": "pm-engineering",
-  "version": "1.0.0",
-  "description": "Engineering & tech skills: Code Review Checklist, Incident Postmortem, API Docs Writer, Architecture Decision Record. Structured outputs for engineering teams and technical PMs.",
+  "version": "2.0.0",
+  "description": "Engineering & tech skills: Code Review Checklist, Incident Postmortem, API Docs Writer, Architecture Decision Record, Debugging Log Analyser, PR Description Writer, System Design Interview, Changelog Generator, Test Strategy Doc, Runbook Writer. 10 structured skills for engineering teams and technical PMs.",
   "author": {
     "name": "Mohit Aggarwal",
     "email": "mohit15856@gmail.com"
   },
   "homepage": "https://github.com/mohitagw15856/pm-claude-skills",
   "license": "MIT",
-  "keywords": ["product-management", "engineering", "code-review", "incident-postmortem", "api-documentation", "adr", "architecture"]
+  "keywords": ["product-management", "engineering", "code-review", "incident-postmortem", "api-documentation", "adr", "architecture", "debugging", "pull-request", "system-design", "changelog", "test-strategy", "runbook", "devops"]
 }