Link GitHub issues to Pardner execution tasks

[depatchedmode]

Problem

Project-level commitments need a durable GitHub identity, while assignments, agent sessions, handoffs, and detailed execution context belong in Pardner. There is no implemented connection between those two levels today.

Proposed goal

Support deliberate publication and linking without creating two mirrored task lists. One GitHub issue may correspond to several Pardner execution tasks. Final integration details should be agreed before implementation.

Acceptance criteria

• Link an existing GitHub issue to one or more Pardner tasks and navigate back to the issue.
• Explicitly promote a local problem into a GitHub issue with a human-reviewable title, problem statement, and acceptance criteria.
• Publish selected milestone summaries, blockers, PR links, and final results; do not mirror every agent comment or status transition.
• Local creation, assignment, comments, and completion continue with GitHub unavailable.
• Publication failures are visible; retries are deduplicated and do not create duplicate issues or comments.
• Define authority for issue-level outcomes versus execution-task state; avoid automatic issue closure from a single completed subtask.
• External writes require authorized credentials and explicit publication intent; private local context is not exported automatically.
• Tests cover one-to-many links, offline work, failed publication, retry, and reconnection.

Boundary

GitHub owns the project-level problem and resolution. Pardner owns execution context, assignments, handoffs, and evidence. Start after phone access and event-driven agent wake-up work.

Related work

Recommended sequencing: #49, then #50, then #51, then this integration.