Rework: expand --focus to handle issue refs instead of separate --issue flag

[akashgit]

PR #210 review and user feedback identified a fundamental design problem: adding --issue as a separate flag creates unnecessary complexity. Instead, --focus should be expanded to detect issue references automatically.

Problem

• --issue duplicates --focus semantics — both mean "build exactly this one thing"
• Adding --issue required 5+ mutual exclusion checks duplicated across cmd_ceo and cmd_run
• The duplication already caused a bug: missing --mode research mutual exclusion in cmd_run
• Two flags that serve the same purpose confuse users

Solution

Expand --focus to detect issue refs (bare numbers, URLs, owner/repo#N) using parse_issue_ref from factory/issue.py. When detected, fetch the issue and use it as the focus spec.

factory ceo /path --focus 42
factory ceo /path --focus "https://github.com/owner/repo/issues/42"
factory ceo /path --focus "owner/repo#42"
factory ceo /path --focus "dashboard UI"  # existing behavior unchanged

Changes needed

1. Remove --issue flag from ceo and run subparsers
2. In --focus resolution: try parse_issue_ref first; if it matches, fetch issue and format as spec; otherwise treat as backlog item name
3. Remove all --issue-specific mutual exclusion checks (they collapse into existing --focus exclusions)
4. Update _build_ceo_task to accept issue metadata from focus resolution
5. Update tests
6. Update CEO prompt to document --focus accepting issue refs

Subsumes

• Bug: missing --mode research + --issue mutual exclusion in cmd_run
• Quality: duplicated issue-handling code between cmd_ceo and cmd_run
• Style: kwargs formatting (the kwargs go away)

Refs: PR #210, issue #202

[akashgit]

Fixed in PR #213.

The --issue flag from PR #210 was removed. --focus now auto-detects issue references (bare numbers, URLs, owner/repo#N shorthand) via is_issue_ref() in factory/issue.py. This eliminated:

• The separate --issue flag and all its mutual exclusion checks
• Code duplication between cmd_ceo and cmd_run (shared _resolve_focus_issue() helper)
• The missing --mode research mutual exclusion bug in cmd_run

Usage is just --focus 42 or --focus "https://github.com/o/r/issues/42" — no new flags to learn.