fix(acp): improve Zed integration (salvage of #11716)

[teknium1]

Summary

Salvage of #11716 onto current main — preserves Henkey's authorship via cherry-pick.

Improves Hermes ACP behavior for Zed so the editor renders rich UI (model picker, diffs, session history) instead of falling back to default states.

Changes

• acp_adapter/server.py: return SessionModelState on new/load/resume; provider-aware provider:model resolution for ACP model switching; title + updated_at in session listing; auto-title after first real exchange
• acp_adapter/session.py: cwd filtering with Windows/WSL path normalization; hide empty threads; sort by most recent activity; title/preview fallback
• acp_adapter/tools.py: emit structured tool_diff_content for patch/write_file on both start AND completion (previously start had diffs but completion degraded to plain-text JSON cards); V4A patch parser + unified-diff parser
• acp_adapter/events.py: capture edit snapshots at tool start, thread args/snapshot metadata into completion events
• run_agent.py: pass tool arguments through step callback metadata so ACP completion rendering has enough context (+1 line)
• scripts/release.py: AUTHOR_MAP entry for @HenkDz (+1 line)
• tests/acp/test_{events,mcp_e2e,server,session,tools}.py: regression coverage for model state, session history metadata, ordering, diff rendering, completion-event behavior

Why salvage instead of direct merge

Original PR branched 63 commits behind main. A direct merge would have deleted release_clients() from run_agent.py (added in #11565), wiped ~22 recent AUTHOR_MAP entries, and reverted test_agent_cache.py (782 lines), dingtalk_auth.py, cron scheduler rework, and Discord/Weixin/dingtalk changes. Cherry-picking the author's 2 intentional commits (444548c5 + 620d71b6) onto current main applies only the intended changes.

Validation

	Result
py_compile all 5 changed .py files	✅ pass
scripts/run_tests.sh tests/acp/	✅ 143 passed, 7 warnings, 16.9s
release_clients() preserved in run_agent.py	✅ line 3245
Recent AUTHOR_MAP entries preserved	✅ kevinskysunny, anthhub, shenuu, xiayh0107 intact
Diff vs origin/main	✅ only the 11 intended files, no staleness artifacts

Attribution

Original PR: #11716 by @HenkDz. Both commits cherry-picked with Author: Henkey <noonou7@gmail.com> preserved. Closing #11716 with credit after merge.