fix(ci): catalog sync, markdownlint, unicode safety, unsupported frontmatter key

catalog:sync: update skill count 261→265 in README.md, AGENTS.md,
docs/zh-CN/AGENTS.md, .claude-plugin/plugin.json

markdownlint:
- MD009: strip trailing spaces in 10_purpose-why, 20_positioning,
  40_personality-archetype, 50_voice-tone, 60_narrative-story, 90_SYNTHESIS
  (both skills/ and .agents/skills/ copies)
- MD037: wrap ___ placeholders in backticks in 70_founder-tension.md:39
- MD028: replace blank lines inside blockquotes with bare > in 90_SYNTHESIS.md

unicode-safety: replace U+2194 (↔) with ASCII <-> in 50_voice-tone.md and
competitive-report-structure/SKILL.md (both copies)

codex-validator: remove unsupported `origin: community` key from
brand-discovery, competitive-platform-analysis, competitive-report-structure,
benchmark-methodology SKILL.md files (both copies)

AGENTS.md

@@ -1,6 +1,6 @@
 # Everything Claude Code (ECC) — Agent Instructions
 
-This is a **production-ready AI coding plugin** providing 64 specialized agents, 262 skills, 84 commands, and automated hook workflows for software development.
+This is a **production-ready AI coding plugin** providing 64 specialized agents, 269 skills, 84 commands, and automated hook workflows for software development.
 
 **Version:** 2.0.0
 
@@ -150,7 +150,7 @@ Troubleshoot failures: check test isolation → verify mocks → fix implementat
 
 ```
 agents/          — 64 specialized subagents
-skills/          — 262 workflow skills and domain knowledge
+skills/          — 269 workflow skills and domain knowledge
 commands/        — 84 slash commands
 hooks/           — Trigger-based automations
 rules/           — Always-follow guidelines (common + per-language)