[Stage 0.1] Define the v1 maintenance and release policy

[draedful]

Parent: #310

Goal

Define the operating contract for the v1 maintenance line before changing branches or release automation.

Scope

• Select and record the exact commit used to create release/v1.
• Confirm whether the post-v1.11.1 connection fix from PR fix(connections): guard isPointInStroke before graph initialization #307 is included in the split point.
• Define which changes are accepted in v1: bug fixes, security fixes, documentation, and any explicitly approved backward-compatible changes.
• State that v1 and v2 are not merged or synchronized automatically.
• Define how a defect affecting both lines is handled through separate issues and pull requests.
• Define the version constraints:
  • release/v1 may publish only 1.x.
  • main may publish only 2.x, or publishing from main remains disabled until v2 is ready.
• Define the npm dist-tag transition for latest, next, and the maintained v1 line.

Acceptance criteria

• The split commit is explicitly recorded and approved.
• The allowed scope of v1 changes is documented.
• The no-sync policy between v1 and v2 is documented.
• The release branch and major-version constraints are documented.
• The npm dist-tag policy before and after the stable v2 release is documented.
• The agreed policy is available in repository documentation or an ADR.