ci(issues): enforce the delivery label rules with one issue-state workflow

[V3RON]

Summary

Third of three stacked PRs. One workflow, issue-state.yml, is the single place that enforces the label rules mechanically. Six jobs, all through actions/github-script (pinned to a SHA like the rest of CI), no third-party actions:

Job	Trigger	Effect
exclusive-label	issues.labeled with a <kind>:<state> label	removes every other state label, so each transition is a single add
task-ready	issues.edited (body) and issues.closed	task:draft → task:ready when the approval box is ticked, the Technical spec section has content, and every #n under Depends on is closed. On close, re-evaluates every open draft that depends on the closed issue
needs-info-reply	issue_comment.created by the issue author on bug:needs-info	→ bug:triage
feature-verify	issues.closed	if the parent is feature:planned and subIssuesSummary.completed == total, comments that completion conditions are due
branch-matches-issue	pull_request opened/edited/synchronize	a PR from a <kind>/<n> branch fails unless its body closes #<n> and no other issue; other branches are ignored
stale-needs-info	daily schedule / dispatch	bug:needs-info untouched for 14 days closes as not planned with a comment

Actions taken with the workflow token do not re-trigger the workflow, so each job removes the label it replaces itself rather than relying on exclusive-label.

The four judgment transitions stay manual on purpose: bug:new → bug:triage, bug:triage → bug:ready, feature:spec → feature:ready, and ticking a task's approval box. Documented in a new Automation section of docs/internal/agent-rules/delivery.md.

Verified

The body parser (section, dependencies, specified, approved) was run against docs/internal/templates/task.md blank and filled: blank → not approved, not specified, no deps; filled → approved, specified, deps parsed; #NNN placeholder is not read as a dependency. The workflow YAML parses. The jobs themselves need a live issue to exercise, which happens after PR 1's labels exist.

Stack

1. model, forms, templates, labels
2. skills
3. this PR — automation