chore: retire the Everything Claude Code name, ECC only (#3330)

* chore: retire the Everything Claude Code name, ECC only

Replace the expanded product name and the everything-claude-code slug
with ECC across READMEs, translated docs, harness folders, skills,
commands, scripts and examples. Repo URLs now point at affaan-m/ECC.

Rename repo-internal artifacts to ecc forms (ecc-conventions skill,
ecc-guardrails, ecc-research-playbook, ecc-team-config, ecc-instincts
with ecc-* ids) and update .claude/ecc-tools.json.

Legacy install ids, plugin dirs, package names and MCP prefixes stay
where existing installs resolve against them. The codex global-state
check and harness-audit repo detection accept the new name first and
the legacy one as a fallback. The Discord bot prefers ~/GitHub/ECC and
falls back to the nested legacy checkout path.

Refresh the skill-triggers registryDigest for the changed skill text.

* fix(ecc-tools): drop managed paths to the removed Claude repo skill

.claude/skills/<repo-skill>/SKILL.md was deleted in #2770 but stayed listed in
ecc-tools.json and the team config. Remove those entries and point the Claude
Code adapter at the existing .agents/skills/ecc-conventions/SKILL.md.

the-shortform-guide.md

@@ -1,4 +1,4 @@
-# The Shorthand Guide to Everything Claude Code
+# The Shorthand Guide to ECC
 
 ![Header: Anthropic Hackathon Winner - Tips & Tricks for Claude Code](./assets/images/shortform/00-header.png)