Throughstone v1.5.0

A risk visibility and release-notes workflow release: it adds a canonical accepted risk /
technical debt register, introduces a reusable release-notes template, and tightens the
architecture-session flow around consciously deferred work before the release is merged or
tagged.

Added

• Accepted risk and technical debt register (registries/risks.yml): a compact,
  machine-readable index for known accepted risks and deferred technical debt, with each row
  pointing to the durable source artifact that carries the full context.
• Release notes template (templates/release-notes.md): a lightweight milestone artifact
  focused on user-visible changes, action required, known issues, documentation, and technical
  references.
• Method and agent guidance requiring accepted risks to stay visible, with a source architecture
  section, ADR, issue/follow-up STEP, incident report, or check-in report created or referenced
  before a risk-register row is added.

Changed

• METHOD.md is now Method version 0.3 (beta).
• Conditional architecture sessions now record Include, Deferred, or N/A with a reason
  and revisit trigger.
• Conditional-session ownership is clearer: Native app is decided by Architecture Overview,
  Privacy/compliance by Data Model or Security, and Identity/auth by Security.
• STEP-1 bootstrap behavior is documented as a special case: init.sh reserves STEP-1, kickoff
  creates the STEP-1 PLAN, then flips it to In progress and uses step-0001-architecture
  wherever branch-per-STEP applies.
• Release/deploy and milestone-doc guidance now points agents to the release-notes template while
  keeping user-facing documentation optional and explicit.
• STEP index path wording now distinguishes workspace-root paths from docs-hub-relative paths.

Fixed

• status.sh now stops resolving STEP-1 when a substep has an unrecognized status or when no
  runnable open substep can be derived.
• Malformed STEP-index state now points users toward scripts/check.sh instead of silently
  skipping ahead.