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.

tests/opencode-config.test.js

@@ -119,7 +119,7 @@ if (
 
       // Regression guard for #2477: opencode registers these agents unscoped
       // in opencode.json's `agent` map, so ANY namespace-scoped id
-      // (`<plugin>:<agent>` — e.g. the Claude Code `everything-claude-code:`
+      // (`<plugin>:<agent>` — e.g. the legacy Claude Code `everything-claude-code:`
       // prefix) fails to resolve ("Agent not found") and hard-breaks subtask
       // commands like /code-review on opencode. Reject the whole scoped class,
       // not just the one legacy prefix.