CON-2: Finish Linear-first pre-submission compliance

[swainjo]

Linear

https://linear.app/happy-stay-days/issue/CON-2/finish-pre-submission-compliance-for-linear-first-upstream-pr

Summary

• Adds optional Linear-first Conductor tracks (conductor/linear.md opt-in; file-based default unchanged).
• Documents Cursor as a first-class install target (local plugin symlink) and adds .cursor-plugin/plugin.json.
• Leaves VERSION at 0.3.0. This is a new PR (does not revive feat: optional Linear-first mode for Conductor tracks #185). Head is swainjo:pr/con-2-linear-first, not swainjo:main.

Test plan

• uv run --with pytest pytest skills/conductor-setup/assets/linear/tests/
• File-based default still works without linear.md
• Linear opt-in smoke (create/link track, handoff, no auto-Done)
• CI: check-changes and cla/google green

Made with Cursor

[google-cla]

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[swainjo]

Superseded by a clean branch split (CON-3 Phase A). This head mixed Linear-first + linear-handoff + Cursor install; those will land as separate upstream-ready branches from upstream/main:

• swainjo:pr/linear-first — Linear-first engine + linear-issues / linear-review / linear-label-review (no linear-handoff, no Cursor)
• swainjo:pr/conductor-handoff — file-based conductor-handoff only
• Cursor install / linear-handoff reconcile follow separately (CON-3 Phase B)

Closing this PR; do not merge.

[swainjo]

Closed as superseded by the CON-3 clean branch split (pr/linear-first, pr/conductor-handoff).