Feature: cross-cycle task queries (`tasks --cycle all|<name>|<id>`)

[muqsitnawaz]

What's missing

`linear tasks --cycle` only accepts `active` or `next`:

```
$ linear tasks --help
--cycle {active,next}
```

There is no way from the CLI to:

• List all open tasks across all cycles (`--cycle all` or omit cycle filter entirely)
• Filter by a specific past or future cycle by name or ID (`--cycle "Q2W11"`)

Why it matters

End-of-cycle triage and quarterly cleanup both need to ask "what's still open in cycles other than the active one?" Today `linear tasks --all --status open` returns only the active cycle's open issues because the CLI hard-pins to `activeCycle`.

For agents draining a backlog or doing scoped cleanup, the answer can't be "drop to GraphQL."

Proposed surface

```
linear tasks --cycle all # every cycle, including completed
linear tasks --cycle backlog # tickets with no cycle assignment
linear tasks --cycle # fuzzy match
linear tasks --cycle # exact uuid
linear tasks --since 2026-06-01 # by date as an alternative cut
```

The implementation likely changes `list_tasks` (line 615 area) to:

• If `--cycle all`: drop the `team.activeCycle.issues` nesting and query `issues(filter: { team: ..., state: ... })` directly
• If `--cycle backlog`: same, with `cycle: { null: true }`
• If `--cycle <name|id>`: resolve to an ID, then filter `cycle: { id: { eq: ... } }`

Related

• Bug: tasks --cycle next errors with 'Cannot query field "nextCycle" on type "Team"' #3 (`--cycle next` bug — same code path)
• Feature: cycle management (create / update / delete) + expose IDs #4 (cycles management — exposes the IDs this feature needs)