docs: sync PRs #874-#887 to aeon docs

[aaronjmars]

Syncs merged aeonfun/aeon PRs onto the downstream doc surfaces. The true watermark was #873 (the prior in-repo sync PR + the website changelog both already carried everything through #873). This batch documents the stragglers merged after it.

PR window

#874 - #887 (10 PRs: 7 signal, 3 maintenance). Sync PRs #861 and #873 skipped per convention (they are prior runs' own aeon-side syncs).

Surfaces changed (this repo)

• CHANGELOG.md [Unreleased]
  • Added - /aeon operator skill installable as a Claude Code plugin (feat: package aeon operator skill as a Claude Code plugin #884, docs: document the aeon setup skill as an installable Claude Code plugin #885); five ecosystem partners in docs/ECOSYSTEM.md (docs(ecosystem): add AgentLink, AI2Human, Mneme, Skim, TaskMarket #880)
  • Changed - OpenRouter gateway traffic attributed to Aeon via HTTP-Referer/X-Title (Tag OpenRouter traffic for the app leaderboard #881); Langfuse v4 compatibility documented (docs(langfuse): note v4 compatibility + ingestion-version header #883)
  • Fixed - aeon-update no longer silently deletes a currently-enabled skill retired upstream (fix(aeon-update): don't silently delete a currently-enabled skill retired upstream #874); pi + OpenRouter onboarding, tsx runtime dep + dashboard run-gate message (fix: pi/openrouter onboarding (CLI tsx runtime + dashboard run-gate) #882)
  • Security - nanoid bumped to 3.3.18 in the remotion project lockfile (security: bump nanoid to 3.3.18 (GHSA-2v37-7h3g-55p8) #879)
  • Maintenance - ponytail-audit dead-code sweep net -444 (refactor: ponytail-audit verified dead-code cuts (net -444) #886); PR-scoped CI concurrency (ci: add PR-scoped concurrency to lint/check workflows #887)
• .claude/skills/aeon/** setup skill - catalog count 73 -> 75 (SKILL.md, references/{layout,mcp,skill-anatomy}.md): totals, all N skills, N skills / 1 enabled, survey denominators (43 of 75 lead-with-Steps, 62 of 75 run-log; ./notify numerator 61 kept), and the pack breakdown Crypto 14 -> 15 / Productivity 10 -> 11.
• plugin/skills/aeon/** setup-skill plugin copy - identical 73 -> 75 bumps; the two trees remain byte-identical except the 5 ${CLAUDE_PLUGIN_ROOT} transform lines (verified: CLAUDE_PLUGIN_ROOT x5, .claude/skills/aeon x0 in the plugin copy).

Not touched (already correct)

• README + docs/skill-packs.md exact counts already show 75 (each new-skill PR regenerated them on merge; validate-readme-catalog.mjs passes). The 60+ marketing floor (docs: express headline skill count as a stable 60+ floor #859) left as-is per convention.
• docs/ECOSYSTEM.md already carries the five partners (docs(ecosystem): add AgentLink, AI2Human, Mneme, Skim, TaskMarket #880 merged here); docs/langfuse.md already carries the v4 note (docs(langfuse): note v4 compatibility + ingestion-version header #883 merged here).

Noise bundled as maintenance

• security: bump nanoid to 3.3.18 (GHSA-2v37-7h3g-55p8) #879 (nanoid remotion lockfile, security), refactor: ponytail-audit verified dead-code cuts (net -444) #886 (ponytail dead-code refactor), ci: add PR-scoped concurrency to lint/check workflows #887 (CI concurrency).

Watermark

New sync watermark: #887.