Human-friendly workspace branch naming

[manuelkiessling]

Summary

Implements human-friendly workspace branch naming as specified in #67.

Format: <YYYY-MM-DD H:i:s>-usermailATdomainDOTtld-SHORTWORKSPACEID

Example: 2025-02-05 14:30:22-manuelATkiesslingDOTnet-a1b2c3d4

Changes

• BranchNameGenerator (Domain): generates branch names with timestamp, sanitized user email (@→AT, .→DOT), and short workspace ID (first 8 chars).
• User email required in setup flow:
  • dispatchSetupIfNeeded(projectId, userEmail) on facade and interface.
  • SetupWorkspaceMessage(workspaceId, userEmail).
  • WorkspaceSetupService::setup(workspace, userEmail).
• Call sites: Controller passes $accountInfo->email; prefab subscriber resolves $event->accountCoreId via AccountFacade and passes account email (throws if account not found).
• BranchNameGeneratorInterface for domain-service-interface-only rule; wired in config/services.yaml.
• Unit tests: BranchNameGeneratorTest (format, email sanitization, short ID).
• Docs: project-workspace-conversation-workflow-high-level.md updated to new format.

Checklist

• New branches use the required format when user email is passed.
• User email is required from both call sites (controller + prefab subscriber).
• Existing workspaces unchanged; only new setups use the new format.
• Branch names valid for Git/GitHub.
• Unit tests for the formatter.
• mise run quality and mise run tests and mise run tests:frontend pass.

Fixes #67