issue list is missing the --project picker #11

lc issue list doesn't support filtering by project, even though the domain layer already has everything needed for it:

• LinearCli.Linear.Issue's :list action already declares argument :project_id, :string, allow_nil?: true
• LinearCli.Linear.Issue.Read.List.build_filter/1 already has a working maybe_put_project_filter/2 clause that turns a project_id into the GraphQL filter

Ported from Ruby's commands/issue/list.rb (option :project, aliases: ['-p'], desc: 'Show issues for only this project. Can be name, URL, ID, or - to select from a list', resolved via CLI::Projects#project_for against Project.all - workspace-wide, not team-scoped).

The gap is purely at the CLI edge:

• LinearCli.CLI.spec/0's issue list subcommand never got a --project/-p option
• LinearCli.CLI.Commands.issue_list/1 never resolves one or passes project_id into the input map it builds

commands.ex's own moduledoc flags this: "--project/-p ... isn't wired up yet - deferred to the phase that builds Owl-based prompts." That phase (6) wired the picker into issue create/issue update but missed issue list.

Fix: add the --project/-p option to issue list's spec, and resolve it the same way issue create does (LinearCli.CLI.Projects.project_for/2 against Linear.projects(), prompting interactively when ambiguous or omitted-but-requested), passing the resolved project.id through as project_id.