docs: add ModelScope AgentID onboarding

[cyruszhang]

No description provided.

[claude]

Review

Docs-only change (README/docs/client.md/SDK README/skill files) — no source, tests, or CLI code touched. Verified the documented commands/flags against the current implementation in packages/dojozero-client/src/dojozero_client/_cli.py and _credentials.py:

• --agentid-agent-id, --agentid-kid, --agentid-key, --agentid-idp-url, --agentid-audience all exist as p_config arguments, and the agentid extra (agent-id-client-sdk>=0.4.0) is declared in packages/dojozero-client/pyproject.toml — matches pip install "dojozero-client[agentid]".
• bet, predict, predictions, bets, events, status, discover, leave subcommands and their positional/trial_id args all match _cli.py's argparse setup.
• The README's new "FIFA World Cup-style trials" claim checks out — packages/dojozero/src/dojozero/world_cup/ exists as a full scenario package.
• credentials.json mode-0600 / save_agentid / has_agentid / load_agentid claims match _credentials.py.

No correctness issues found. A few minor points, non-blocking:

1. README.md — the new bullet says "Connect external agents with the dojozero-client SDK, including GitHub/API-key auth or ModelScope AgentID auth" but then only shows the pip install step before jumping to dojozero-agent config --github-token; the ModelScope block is a second, separate pip install + config snippet inserted mid-flow. Slightly disjointed but not incorrect — a reader following top-to-bottom will still end up with a working config.
2. docs/client.md — the Chinese-language "DojoZero Agent 接入说明" section is a fairly large, dense addition to an otherwise English doc. Consider whether this belongs in a separate localized doc (e.g. docs/client.zh-CN.md) rather than inline in the middle of the English guide — future edits to the English content risk drifting out of sync with the untranslated block, and non-Chinese-reading maintainers can't verify future changes to it. Not a blocker, but worth a call on doc structure.
3. skills/dojozero-player/SKILL.md / skills/dojozero-predictor/SKILL.md — the removed line referencing the AgentID Client SDK guide (../../../agent-identity/docs/agentid-client-sdk.md) is replaced with generic guidance ("register through ModelScope's AgentID identity service or the matching ModelScope skill/API"). Reasonable if that internal doc path was never valid for external repo consumers, but worth confirming it wasn't intentionally referencing a real internal doc that's now silently dropped.
4. No new secrets, credentials, or executable code introduced — nothing security-sensitive beyond documentation correctness, which was verified above.

Nothing here blocks merge; this is a good, verifiable documentation update.