/sessions returns empty despite sessions existing in database (workspace_id = NULL, empty workspace table)

Description

Environment

• OpenCode 1.18.4 (npm)
• Linux / WSL2
• 7 sessions, 281 messages, 893 parts in DB

Steps

1. Create multiple sessions over time in a workspace directory
2. Run /sessions
3. Shows "no sessions" but SELECT COUNT(*) FROM session returns 7

Root Cause

1. All sessions have workspace_id = NULL, workspace table empty

All 7 sessions have workspace_id=NULL. Workspace table has 0 rows.
Migration 20260227213759_add_session_workspace_id added FK column without backfill.

2. V2 state tables all empty

session_message: 0 rows, session_input: 0 rows, session_context_epoch: 0 rows
But message: 281 rows, part: 893 rows, all with valid session_id FKs.
Migration reset_v2_session_state cleared v2 tables without migrating legacy data.

3. Event table uses aggregate_id not session_id

If session listing joins on session_id against events, it fails.

Fix Suggestions

Short-term

Session listing should fall back to directory matching when workspace_id is NULL:
function listSessions(dir) {
let sessions = db.sessions.where({ workspace_id: currentWorkspaceId });
if (!sessions.length) sessions = db.sessions.where({ workspace_id: null, directory: dir });
if (!sessions.length) sessions = db.sessions.all();
return sessions;
}

Medium-term

Backfill workspace entries and link orphaned sessions via SQL migration.

Long-term

Ensure workspace exists and is linked at session creation time.

Impact

Sessions inaccessible via /sessions, /resume, /continue despite intact data.

Database inspection (via sqlite3) shows three compounding issues:

1. All 7 sessions have workspace_id = NULL. The workspace table is
   empty (0 rows). Migration 20260227213759_add_session_workspace_id
   added the FK column without backfilling existing data.

2. V2 state tables (session_message, session_input, session_context_
   epoch) are all 0 rows. But the message table has 281 rows and the
   part table has 893 rows, all with valid session_id FKs. Migration
   reset_v2_session_state cleared v2 tables without migrating legacy data.

3. The event table uses aggregate_id not session_id. If /sessions joins
   on session_id against events, it will fail silently.

Fix: /sessions should fall back to directory-based matching when
workspace_id is NULL, so sessions are always discoverable regardless
of workspace migration state.

Plugins

none

OpenCode version

1.18.4

Steps to reproduce

1. cd /home/samuel/Documents/Opencode\ Workspace
2. opencode
3. Create a session and do some work
4. Quit and restart, or open a new session with /new
5. Run /sessions
6. Result: reports "no sessions"
7. But sqlite3 ~/.local/share/opencode/opencode.db "SELECT COUNT(*) FROM session" returns 7

The bug is consistent — happens every time /sessions is invoked.

Screenshot and/or share link

No response

Operating System

Debian GNU/Linux 13 (trixie), x86_64, kernel 6.12.95

Terminal

xfce4-terminal (xterm-256color, X11)