feat: add cycle list/view commands and issue list --cycle filter

[regaw-leinad]

Summary

• Add linear cycle list and linear cycle view commands for browsing team cycles
• Add --cycle filter to linear issue list for filtering issues by cycle
• Regenerate skill docs to include new commands

Problem

PR #150 added cycle support to issue create/update/view, but there was no way to browse cycles themselves or filter issue lists by cycle. Users had to know cycle names/numbers without being able to look them up from the CLI. See #64.

Fix

Adds a cycle command group (aliased cy) with two subcommands, following the same patterns as the existing milestone commands:

cycle list shows all cycles for a team with number, name, dates, and status. Active cycle is highlighted in green, upcoming cycles use default color, and completed/past cycles are muted.

$ linear cycle list --team XXX
#  NAME       START      END        STATUS
3  Sprint 3   2026-03-10 2026-03-24 Upcoming
2  Sprint 2   2026-02-24 2026-03-10 Active
1  Sprint 1   2026-02-10 2026-02-24 Completed

cycle view shows full cycle details including a progress indicator, description, issue breakdown by state, and first 10 issues. Accepts cycle name, number, or "active".

$ linear cycle view active --team XXX
# Sprint 2

**Number:** 2
**Start:** 2026-02-24
**End:** 2026-03-10
**Status:** Active
**Team:** MyTeam (XXX)

## Issues

**Progress:** 17/50 (34%)
**Total Issues:** 50
**Completed:** 17
**In Progress:** 12
**To Do:** 21

**Issues:**
- XXX-412: Fix auth token refresh (In Progress)
- XXX-398: Add dark mode toggle (Todo)
...

issue list --cycle filters the issue list to a specific cycle, reusing the existing getCycleIdByNameOrNumber() utility and the GraphQL IssueFilter.cycle field.

$ linear issue list --cycle active --team XXX --sort priority
◌   ID      TITLE                  LABELS          E STATE UPDATED
--- XXX-101 Some task              Backend, Feature - Todo  1 day ago
--- XXX-102 Another task           Feature          - Todo  1 day ago

Why

Cycles are a core part of the Linear workflow and the CLI should support browsing them. cycle list lets you see what's available, cycle view gives you sprint progress at a glance, and --cycle on issue list lets you scope your view to a specific sprint.

Test Plan

• Tested all three commands against a real Linear workspace with 11 cycles and 50+ issues
• cycle view tested with active, by number, and by exact name lookup
• All 220 unit/snapshot tests pass

[schpet]

@regaw-leinad wonderful thank you! i'll take a look at this sometime soon. in the interim, can you let me know if you've tried this out / confirmed it works for you? squinting at it, it looks right, but i always like to ensure some human verification was done.

[regaw-leinad]

@schpet yeah! tested all three commands against my startup's Linear workspace and everything worked. here's what it looks like (changed the actual data but the structure is the same):

$ linear cycle list --team XXX
#  NAME       START      END        STATUS
4  Sprint 4   2026-03-17 2026-03-31 Upcoming
3  Sprint 3   2026-03-03 2026-03-17 Active
2  Sprint 2   2026-02-17 2026-03-03 Completed
1  Sprint 1   2026-02-03 2026-02-17 Completed

$ linear cycle view 3 --team XXX
# Sprint 3
**Number:** 3
**Start:** 2026-03-03
**End:** 2026-03-17
**Status:** Active
**Team:** MyTeam (XXX)

## Issues
**Progress:** 17/50 (34%)
**Total Issues:** 50
**Completed:** 17
**In Progress:** 13
**To Do:** 20

**Issues:**
- XXX-110: Fix dashboard display issue (In Progress)
- XXX-108: Document supported OS versions (In Progress)
- XXX-105: Upgrade dependency to fix vulnerability (Done)
- XXX-101: Some feature request (Todo)
- XXX-100: Another feature request (Todo)
_...and 45 more issues_

$ linear issue list --cycle 3 --team XXX
◌   ID      TITLE                LABELS           E STATE UPDATED
--- XXX-101 Some feature         Backend, Feature - Todo  1 day ago
--- XXX-100 Another feature      Feature, Scout   - Todo  1 day ago

also ran the full test suite, 213 passing.

[schpet]

@regaw-leinad cool! well that's awesome, this has been a gap for a while so i appreciate this. if you notice anything to do with cycles, don't hesitate to make a pr or file an issue – i don't use them so i'm unlikely to notice anything isn't working right.