fix(session): scope default lists by directory

[samiralibabic]

Issue for this PR

Closes #38529
Replaces the implementation scope from #28972 and #18890.

Related to #31210. This is the current-dev implementation for #38529; unlike #31210, it intentionally makes exact-directory filtering the default in both Git and non-Git contexts while retaining project scope when directory filtering is disabled.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Non-git directories share the global project, so project-only session queries can mix unrelated directories.

The CLI now sends its exact instance directory when listing sessions. The TUI uses the same exact-directory filter by default and keeps project scope when directory filtering is disabled. Explicit recursive path behavior is unchanged, and directory queries retain the legacy path IS NULL fallback. Resume-time cwd handling is intentionally out of scope.

How did you verify your code works?

• Focused CLI, TUI, and server session-list tests
• bun typecheck in packages/opencode and packages/tui
• pre-push bun turbo typecheck
• Prettier and git diff --check

Screenshots / recordings

N/A. Query behavior only.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found related PRs that address similar session scoping and directory filtering concerns:

1. PR fix(tui): scope non-git sessions by directory, not hierarchical path #31210 - fix(tui): scope non-git sessions by directory, not hierarchical path

   • Directly related: already implements directory-based scoping for non-git sessions in the TUI

2. PR fix(opencode): scope --continue to the current worktree directory #33521 - fix(opencode): scope --continue to the current worktree directory

   • Related: handles directory scoping for the continue command

3. PR fix(acp): list known sessions across projects on empty cwd #33789 - fix(acp): list known sessions across projects on empty cwd

   • Related: addresses session listing behavior with directory context

4. PR fix(sdk): avoid implicit directory filtering on /session list #20361 - fix(sdk): avoid implicit directory filtering on /session list

   • Related: directly addresses implicit directory filtering on session list endpoints

5. PR fix(opencode): resolve directory when list sessions #22835 - fix(opencode): resolve directory when list sessions

   • Related: handles directory resolution during session listing

These PRs tackle similar problems around session scoping and directory-based filtering. PR #38532 appears to be consolidating these fixes into a comprehensive solution (as indicated by "Replaces the implementation scope from #28972 and #18890" in the description).