fix(tui): load root sessions safely in dialogs

[CasualDeveloper]

Issue for this PR

Closes #16270
Closes #31125
Partially addresses #13877
Supersedes #23276, #24383, #26432

Type of change

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

What does this PR do?

Problem: Session dialogs built options from mixed or not-yet-loaded session data, which let child sessions crowd out roots and could freeze an empty browse order during startup.

Solution:

• Request root sessions from dialog-local browse and search resources.
• Freeze browse order only after the root browse load resolves.
• Share query/order helpers across both TUI session dialog implementations.

How did you verify your code works?

• bun test test/cli/tui/dialog-session-list.test.ts
• bun typecheck
• git diff --check
• Pre-push hook: bun turbo typecheck

Screenshots / recordings

N/A. This changes session query/loading behavior, not the rendered layout.

Notes

• AI Assistance: OpenCode + openai/gpt-5.5
• Review: Human operator reviewed

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 a related PR:

PR #26432: fix(tui): request root sessions in session dialog

• URL: fix(tui): request root sessions in session dialog #26432
• Why it's related: This PR is directly superseded by the current PR (as noted in the description: "Supersedes fix(tui): request root sessions in session dialog #26432"). PR fix(tui): request root sessions in session dialog #26432 addresses the same issue of requesting root sessions in session dialogs, which is the core problem being fixed by PR fix(tui): load root sessions safely in dialogs #31132.

The current PR (#31132) represents an improved/updated fix that builds upon the earlier approach in #26432.

[antomicblitz]

Yes please 👍