feat: add --issue flag to factory ceo/run for direct issue targeting

[akashgit]

Factory experiment #54. Hypothesis: Add --issue flag to factory ceo and factory run for GitHub/GitLab issue targeting (issue #202).

What to Build

1. New module factory/issue.py with:

   • IssueSpec dataclass: number, title, body, labels, url, forge
   • parse_issue_ref(ref: str, project_path: Path) → (forge, owner_repo, number) — handles bare numbers, GitHub URLs, GitLab URLs, owner/repo#N shorthand
   • infer_remote(project_path: Path) → (forge, owner_repo) — parses git remote get-url origin for HTTPS and SSH remotes
   • fetch_issue(issue_ref: str, project_path: Path) → IssueSpec — fetches via gh issue view (GitHub) or glab issue view (GitLab)
   • format_issue_as_spec(spec: IssueSpec) → markdown string

2. CLI modifications in factory/cli.py:

   • Add --issue argparse arg to both ceo and run subparsers
   • Add mutual-exclusion validation (vs --prompt, --focus, --no-github, --mode interactive)
   • Wire into cmd_ceo and cmd_run: fetch → format → persist to .factory/strategy/current.md → pass as context
   • Update _build_ceo_task with issue_number/issue_url params for Directive + finalize tracking

3. Tests in tests/test_issue.py:

   • URL parsing (GitHub, GitLab, bare number, shorthand)
   • Remote inference (HTTPS, SSH)
   • Spec formatting
   • Subprocess mocking for fetch
   • CLI mutual-exclusion errors

Acceptance Criteria

• factory ceo /path --issue 42 fetches issue ACE self-improvement: evolve agent playbooks from experiment data #42 and runs as spec
• factory ceo /path --issue https://github.com/owner/repo/issues/42 works with full URL
• factory ceo /path --issue 42 --prompt foo.md errors (mutual exclusion)
• factory ceo /path --issue 42 --no-github errors
• All unit tests pass
• Lint and type check clean
• Eval score does not regress

Constraints

• Read CLAUDE.md before starting
• Do NOT modify eval/score.py or .factory/
• Follow the --prompt pattern exactly
• Use subprocess for gh/glab CLI calls

[akashgit]

Superseded by PR #213.

The original --issue flag approach from PR #210 was reworked per review feedback. Instead of a separate flag, --focus was expanded to auto-detect issue references. See issue #211 for the rationale.

Usage: factory ceo /path --focus 42 (or any issue URL / shorthand).