feat: Beads issue integration for workspace creation

[ckrough]

Summary

Implements beads issue tracker integration with agentspaces workspace creation, enabling users to create workspaces directly from issue IDs.

Changes

• Added issue_id field to workspace metadata (schema v3→v4)
• Created beads infrastructure module for CLI integration
• Added create_from_issue() service method
• Added CLI flags: --next-issue and --issue-id
• Updated TUI to display issue information
• Added issue-specific output formatters
• Comprehensive test coverage (12 integration + 14 unit tests)

Commands

# Create workspace from next ready issue
agentspaces workspace create --next-issue

# Create workspace from specific issue
agentspaces workspace create --issue-id=agentspaces-123

Test Results

• 337 tests passing
• 85.27% code coverage
• All quality gates passed (ruff, mypy, bandit)
• @Python-pro review approved

Backward Compatibility

• v3 workspaces load correctly (issue_id defaults to None)
• No migration required
• Existing workspace creation unchanged

[claude]

Code review

Found 1 issue that should be addressed:

Exit code inconsistency in workspace.py

Location: src/agentspaces/cli/workspace.py line 115

Issue: When no ready issues are found with --next-issue, the code calls print_error() but exits with code 0 (success) instead of 1 (error).

Current code:

if not issues:
    print_error("No ready issues found. Create with: bd create")
    raise typer.Exit(0)  # Should be Exit(1)

Why this is a bug:

• The command fails to accomplish its intended task (create a workspace from an issue)
• Exit code 0 indicates success, which is inconsistent with the error message
• All other error conditions in this file consistently use typer.Exit(1) after print_error()
• Scripts or CI pipelines checking exit codes would incorrectly interpret this as successful execution

Fix:

if not issues:
    print_error("No ready issues found. Create with: bd create")
    raise typer.Exit(1)  # Error condition should use exit code 1

Reference: See other error handlers in the same file at lines 100, 107, 139, 142, 162, etc. which all use typer.Exit(1) consistently.

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Otherwise, the code looks good! The implementation follows CLAUDE.md conventions:

• ✅ Type hints on all functions
• ✅ Google-style docstrings
• ✅ Proper error handling
• ✅ Subprocess-based git operations
• ✅ Structured logging with structlog
• ✅ Good test coverage (85.27%)