docs: ADR-007 dev/cloud parity, AGENTS.md section, cursor rule

[wgutmann]

• Add ADR-007: Dev/Cloud Parity and Local-First Testing
• Include 'what needs Cloudflare' table for local vs cloud requirements
• Add non-negotiable Dev/Cloud parity section to AGENTS.md
• Add .cursor/rules/dev-cloud-parity.mdc (alwaysApply) for agent context
• Link ADR-007 in .cursor/docs/architecture.md

Summary

• [What changed]
• [Why it changed]

Traceability (ContextStream / knowledge graph)

Required. Link this PR to the tech plan(s) and PRD so the ContextStream knowledge graph can show PR ↔ Tech Plan ↔ PRD. Use the stable doc IDs from .github/traceability-mapping.yaml.

• Implements (Tech Plan): e.g. TP-SPOC-001 — [list one or more TP-XXX IDs this PR implements, or "none" if doc-only / infra]
• PRD: e.g. PRD-001 — [PRD ID this work traces to, or "none"]
• Doc links: Add markdown links to the PRD and tech plan doc(s) using the traceability mapping. Example: PRD-001, TP-SPOC-001. (Use "none" if doc-only / infra.)
• Labels: Apply traceability labels from .github/labels.yaml (e.g. prd:PRD-001, tech-plan:TP-SPOC-001).

Risk

• [low / medium / high] — [brief rationale]

Test plan

• [test or verification step]

Rollback

• [How to revert if needed]

Product impact

• Does this change scope, requirements, or user-facing copy? (e.g. docs/product/**, docs/brand/**, UI strings, API descriptions, landing copy)
  • If yes: Product review requested. Use the PM review checklist (human PM or agent with product manager personality).
  • If no: Leave unchecked and skip.

[github-actions]

PR traceability check (recommended for ContextStream PR ↔ Tech Plan ↔ PRD):

• PR must have at least one traceability label from .github/labels.yaml (e.g. prd:PRD-001, tech-plan:TP-SPOC-001).

See CONTRIBUTING and the PR template.