migration: V1 "global" project sessions invisible in V2 session list after upgrade #55275

Summary

After upgrading from OpenCode v1.19.0 to v2.0.28, sessions created in V1 under the fallback "global" project no longer appear in the V2 session list (/sessions picker and opencode session list), even when opencode is opened in the exact directory where those sessions were created. The v1→v2 data migration reports completed, but those sessions remain attached to the global project instead of being re-associated with the per-directory project that V2 resolves.

Environment

• opencode version: 2.0.28 (upgraded from 1.19.0)
• OS: Linux 7.0.0-38-generic (linux x64)
• Terminal: TERM=xterm
• Shell: /bin/bash
• Install/channel: npm global @opencode/cli@2.0.28 (latest)
• Active plugins: a local path plugin (loads fine), oh-my-openagent (fails to load — V1 plugin API, unrelated to this issue)

Reproduction

1. On V1 (1.19.0), start opencode in a directory that is NOT a git worktree root — in my case a repo-tool multi-repo checkout (~/workspace/openharmony, has .repo/ but no .git at the root). Create sessions there. In the V1 database these sessions get project_id = "global" (the global project row has worktree = "/").
2. Upgrade to OpenCode v2.0.28. The v1→v2 migration runs and kv["migration.v1-v2"] reports {"phase":"completed"}.
3. Start opencode in the same directory. V2 creates a NEW project row for that directory (e.g. project 225ebdf…, worktree = <that directory>).
4. Open /sessions or run opencode session list. The list is empty.

Expected Behavior

The v1→v2 migration re-associates V1 "global"-project sessions with the project V2 resolves for their directory (or the session list falls back to matching by directory), so history created in V1 stays visible in the same directory after upgrading.

Actual Behavior

• opencode session list in the original directory returns nothing ("List top-level sessions in the current project").
• The sessions still exist in opencode.db (session_v2 table) with project_id = "global" and the correct directory; total counts are unchanged (437 sessions / ~17k messages in my case — no data loss).
• GET /api/session?directory=<dir> and GET /api/session?project=global both return the "missing" sessions, so only the project scoping hides them.
• Sessions created in V1 inside git worktrees (which already had real project IDs in V1) display correctly in V2. Only "global"-project sessions are affected.

Additional Context

• Workaround: POST /api/session/{id}/move with {"directory": "<original directory>"} re-associates a session with the project V2 resolves for that directory. I moved all 392 affected sessions this way and they reappeared in /sessions immediately.
• Caveats of the workaround: move updates time_updated (affects list ordering), and child sessions (subagent runs) do NOT follow their parent, so every session must be moved individually.
• Suggested fix: during the v1→v2 migration, re-resolve project_id for "global" sessions from their directory field so upgraded history stays visible.