Read issue lifecycle state from GitHub without a local mirror

[proerror77]

Parent

#455

What to build

Make the read-only issue show/status commands and PM help/dashboard entrypoints read live GitHub issue state without requiring a local .claude/epics mirror. GitHub labels, assignees, native relationships, and linked pull requests remain authoritative; optional local files may enrich output but never gate it.

Acceptance criteria

• Issue show and issue status read state, labels, assignees, native parent/sub-issues, blocked-by relationships, and linked pull-request state from GitHub.
• A missing .claude/epics directory does not prevent a valid read.
• PM help and dashboard/status entrypoints describe GitHub as authoritative and do not advertise the legacy gh-sub-issue extension as required.
• Read-only commands perform no issue, comment, label, relationship, or repository mutation.
• One focused check covers missing local mirrors, native relationship display, linked pull-request state, and user-facing help/dashboard output.
• Bash syntax, ShellCheck for executable shell snippets, and git diff --check pass.

Blocked by

#456 defines the lifecycle contract and terminology.

Out of scope

• Close, reopen, and evidence sync mutations; those remain Mutate issue lifecycle from GitHub without a local mirror #457.
• PRD publication and initialization; those remain Publish PRD issues with native GitHub relationships #468.
• Historical reconciliation, workflow enforcement, runtime deployment, or trading behavior.