feat: paginate lists, cross-cycle/backlog scopes, assignee filter, states, relations (v0.3.0)

Closes the load-bearing gaps for the agent ticket workflow:

- Pagination: every issue list now follows pageInfo instead of silently
  truncating at Linear's 50-issue default. On a real cycle this surfaced 137
  tasks where the old code showed 50 — the exact cause of 'search before you
  create' missing existing tickets and filing duplicates.
- tasks --cycle all|none: list the whole team (cross-cycle + backlog) or just
  the backlog, not only the active/next cycle.
- tasks --assignee me|none|<email>: filter by real assignee (the queue view
  keyed off agent: labels, not assignment).
- states: list the team's workflow states so agents stop guessing status names.
- update --blocks/--blocked-by/--relates: create issue relations; detail view
  reads them back (blocks / blocked by / related / duplicate).
- Detail view + JSON enriched with project, cycle, parent, url, estimate,
  dueDate, relations (fixes the lossy detail JSON).

Verified end-to-end against a live team.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: muqsitnawaz