Feature: Batch session creation from dashboard

[OneStepAt4time]

Feature Request

Extend the existing "New Session" modal to support creating multiple sessions at once via POST /v1/sessions/batch. The operator specifies a list of work directories (and optional prompts), and Aegis creates all sessions in parallel.

Why

• The competitive analysis positions Aegis as infrastructure for automating CC at scale
• Currently an operator must click "New Session" five times to spin up 5 sessions across 5 repos
• The API client already has batchCreateSessions — zero backend work needed
• Directly supports CI/CD, multi-repo sweeps, and batch operations

Effort

S — Extend existing CreateSessionModal to support a list input, show batch results

API Endpoints

• POST /v1/sessions/batch

Priority

P0 — Low effort, high value for multi-repo workflows

[OneStepAt4time]

Fixed in PR #338. Batch session creation UI with single/batch mode tabs, shared prompt support, and results view. Tests included.