chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis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/yaml-format/spec.md

@@ -0,0 +1,77 @@
+## ADDED Requirements
+
+### Requirement: Workflow definition structure
+A workflow YAML SHALL have a top-level `name`, `description`, and `nodes:` array. It MAY have `provider`, `model`, `interactive`, `mutates_checkout`, `tags`.
+
+#### Scenario: Minimal valid workflow
+- **WHEN** a YAML file contains a `name`, `description`, and at least one node
+- **THEN** the loader SHALL parse it as a valid workflow definition
+
+#### Scenario: Missing name
+- **WHEN** a YAML file lacks a `name` field
+- **THEN** the loader SHALL reject it with a validation error
+
+### Requirement: Seven node types
+The engine SHALL support exactly 7 node types, mutually exclusive per node: `command`, `prompt`, `bash`, `script`, `loop`, `approval`, `cancel`.
+
+#### Scenario: Node with exactly one mode field
+- **WHEN** a node has `prompt:` but no other mode field
+- **THEN** it SHALL be classified as a PromptNode
+
+#### Scenario: Node with multiple mode fields
+- **WHEN** a node has both `prompt:` and `bash:`
+- **THEN** the loader SHALL reject it with a mutual-exclusivity error
+
+#### Scenario: Node with no mode field
+- **WHEN** a node has none of the 7 mode fields
+- **THEN** the loader SHALL reject it
+
+### Requirement: Common node fields
+All node types SHALL support `id`, `depends_on`, `when`, `trigger_rule`, `retry`, `timeout`, `output_type`, `always_run`.
+
+#### Scenario: Node id must be unique
+- **WHEN** two nodes in the same workflow share the same `id`
+- **THEN** the loader SHALL reject the workflow
+
+### Requirement: Prompt node
+A PromptNode SHALL have a `prompt:` string field containing the AI prompt text.
+
+#### Scenario: Empty prompt rejected
+- **WHEN** a node has `prompt: ""`
+- **THEN** the loader SHALL reject it
+
+### Requirement: Bash node
+A BashNode SHALL have a `bash:` string field and MAY have `timeout` (ms). AI-specific fields SHALL be ignored with a warning.
+
+#### Scenario: Bash node with timeout
+- **WHEN** a bash node includes `timeout: 30000`
+- **THEN** the executor SHALL kill the subprocess after 30 seconds
+
+### Requirement: Script node
+A ScriptNode SHALL have `script:` (inline or named), `runtime:` (`bun` or `uv`), MAY have `deps:` and `timeout:`.
+
+#### Scenario: Script with deps
+- **WHEN** a script node has `runtime: bun` and `deps: ["lodash"]`
+- **THEN** the executor SHALL install dependencies before running the script
+
+#### Scenario: Named script from disk
+- **WHEN** `script: analyze` and a file `scripts/analyze.ts` exists
+- **THEN** the executor SHALL load and run it
+
+### Requirement: Loop node
+A LoopNode SHALL have `loop:` with `prompt`, `until`, `max_iterations`, and optional `fresh_context`, `interactive`, `gate_message`, `until_bash`.
+
+#### Scenario: Loop with completion signal
+- **WHEN** the AI response contains the `until` string
+- **THEN** the loop SHALL stop and the node SHALL complete
+
+#### Scenario: Loop exceeds max_iterations
+- **WHEN** the loop reaches `max_iterations` without the completion signal
+- **THEN** the node SHALL fail
+
+### Requirement: Cancel node
+A CancelNode SHALL have a `cancel:` string containing a reason. It SHALL terminate the workflow run.
+
+#### Scenario: Cancel terminates workflow
+- **WHEN** a cancel node executes
+- **THEN** the workflow SHALL be marked as cancelled with the cancel reason