project: no way to remove a project entry (stale dirs accumulate in Ctrl+O) #58197

Summary

There is no way to remove a project entry. Any directory opencode is ever run in (or a session is imported into) becomes a permanent row in the project table and shows up in the Ctrl+O "Open session or project" picker forever, even after every session in it has been deleted. Temp dirs, scratch workspaces, and one-off worktrees accumulate as noise with no supported cleanup.

Environment

• opencode version: 2.0.25
• OS: Darwin 25.6.0 (darwin arm64)
• Terminal: ghostty (TERM=xterm-ghostty, COLORTERM=truecolor)
• Shell: /bin/zsh
• Install/channel: latest (Homebrew)
• Active plugins: none configured globally; a repo-local .opencode/plugins/ spike exists in one project but was not involved

Reproduction

1. cd "$(mktemp -d)" && opencode run "hi" (or opencode session import --directory <tmpdir> file.json).
2. opencode session delete <that session id> so the project has zero sessions.
3. Press Ctrl+O in the TUI, or opencode api get /api/project.

The temp directory is still listed as a project.

Expected Behavior

One of:

• A project.remove operation (API DELETE /api/project/{projectID}, a TUI command in the Ctrl+O picker / command palette, and/or opencode project remove <dir>), ideally refusing or confirming when the project still has sessions.
• Or, at minimum, empty projects being pruned automatically (e.g. when their last session is deleted, or when the canonical directory no longer exists).

Actual Behavior

• The HTTP API only exposes GET /api/project and PATCH /api/project/{projectID} (checked in /openapi.json for 2.0.25); there is no delete.
• The TUI has no remove/hide action for projects; the palette commands touching projects are "Open session or project", "Return to projects", and "Show project worktrees".
• opencode session delete removes the session but leaves the project row.

After importing ~130 sessions from other tools and deleting the junk ones, I was left with 15 dead project entries (macOS $TMPDIR subdirs, Claude desktop scratch-workspaces/…, ~/Downloads, ~/Documents, worktrees that no longer exist). The only way to clean them was to edit opencode.db directly:

PRAGMA foreign_keys = ON;
DELETE FROM project WHERE id IN (...)
  AND (SELECT count(*) FROM session    s WHERE s.project_id = project.id) = 0
  AND (SELECT count(*) FROM session_v2 s WHERE s.project_id = project.id) = 0;

which worked (the project FKs cascade), but is exactly what the troubleshooting docs tell users not to do.

Additional Context

• Reproducible consistently.
• Related: the project list is the only navigation surface for sessions across directories, so stale entries directly degrade Ctrl+O. Even a hidden/archived flag settable via the existing PATCH /api/project/{projectID} would be a workable first step.