feat(workflows): collapse oversized model catalogs in config/validate + config --models; ACP deps currency

[VikashLoomba]

Feature — config/validate model-list collapse (the ask)

Harnesses with large model catalogs (pi, opencode advertise hundreds) dumped every model id inline in the config / validate option tables and in --json, flooding an authoring agent's context. Now any select option above 24 leaf choices (in practice the model option) renders as a grouped summary (total + per-provider/group counts) on both the human table and --json; small catalogs (claude, codex, and every effort/mode/boolean option) are unchanged and print verbatim.

The full list is reachable only through the new config <harness> --models[=<filter>]: bare prints the provider/group breakdown (no leaf ids), =<provider|substring|/regex/> prints the matching leaf ids. There is deliberately no unfiltered full-leaf dump on any surface — neither --json nor --models can flood context. The collapse happens only at the CLI print boundary; the in-memory report and the programmatic probeHarnessConfig() / validateWorkflowScript() returns stay complete, so configOptions validation still checks against every advertised model.

Docs moved with it: the authoring skill reference (+ regenerated author-workflow prompt), docs/specs/config-options.md, the workflows README, and CLI help. New tests in packages/workflows/test/config-model-collapse.test.ts (+ updated config.test.ts for the new pi --json contract). Live-verified: opencode's 601-model catalog collapses to a one-line summary; --models=deepseek returns the matching leaves; claude/codex unchanged.

ACP dependency currency (rode along — the gate blocks all merges when stale)

Mechanical bumps, each classified against the runbook's surface map:

• claude-agent-acp 0.69.0 → 0.70.0 — its only change ("switch providers for loaded Claude sessions" #1002) is adapter-internal; the providers/* wire we consume is SDK-defined (unchanged at 1.3.0) and our client already re-issues providers/set on reconstructed connections. Docs citations moved.
• claude-agent-sdk override 0.3.234 → 0.3.235 — "parity with Claude Code v2.1.235", no API change; wrapped behind the adapter, never imported directly.
• codex-acp upstream sync → 3d56827 — non-squash subtree merge of upstream release 1.5.0 (#409), a release-please version/CHANGELOG bump only, no source change.

Dependency gate, attribution gate, manifest check, build, typecheck all green; full test matrix green (every package 0 fail); codex-acp fork suite 914 pass; pre-push live 4-backend e2e green.

⚠️ Merge with a MERGE COMMIT (not squash) — the branch contains the non-squash codex-acp subtree merge; squashing rewrites it and breaks the dependency gate's upstream-ancestry invariant on main.