chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis
(boocontext-audit, conductor upgrades, self-healing/verify-gate skills):
add-3tier-memory, import-llm-evaluator, import-pregel-engine, plugin-platform,
conductor-evolution, code-intelligence-upgrade, dev-workflow, ui-overhaul,
agent-reliability.

Delete 11 stub archive files (49-66B each, 'Status: Shipped. Archived.' only)
that provide zero documentation value over the existing CHANGELOG.md + git tags.

openspec/changes/archived/2026-06-07-hybrid-workflow-engine/specs/human-approval/spec.md

@@ -0,0 +1,37 @@
+## ADDED Requirements
+
+### Requirement: Approval gate pauses execution
+An ApprovalNode SHALL pause workflow execution and send a message for human review. Execution SHALL only continue when the user approves or rejects.
+
+#### Scenario: Approval pauses workflow
+- **WHEN** an approval node executes
+- **THEN** the workflow status SHALL transition to `paused`
+- **THEN** a message SHALL be sent with the approval message text
+
+#### Scenario: Approve resumes execution
+- **WHEN** the user approves a paused workflow
+- **THEN** the workflow SHALL resume with the next node in the DAG
+
+#### Scenario: Reject fails the node
+- **WHEN** the user rejects a paused workflow
+- **THEN** the node SHALL be marked as failed
+- **THEN** downstream nodes SHALL evaluate their trigger rules
+
+### Requirement: Capture response from approval
+An approval node MAY support `capture_response: true` to store the user's comment as `$nodeId.output`.
+
+#### Scenario: Approval with captured response
+- **WHEN** an approval node has `capture_response: true` and the user provides a comment during approval
+- **THEN** the comment SHALL be stored as the node's output, available via `$nodeId.output`
+
+### Requirement: On-reject retry
+An approval node MAY specify `on_reject` with a `prompt` and optional `max_attempts` for re-presenting after rejection.
+
+#### Scenario: Reject with retry prompt
+- **WHEN** an approval node has `on_reject: { prompt: "..." }` and the user rejects
+- **THEN** the on_reject prompt SHALL be executed (typically the AI revises based on feedback)
+- **THEN** the approval gate SHALL be re-presented to the user
+
+#### Scenario: Max attempts exceeded
+- **WHEN** the number of rejections exceeds `on_reject.max_attempts`
+- **THEN** the node SHALL fail permanently