chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis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/audit-harness-integration/specs/hook-audit-pipeline/spec.md

@@ -0,0 +1,56 @@
+## ADDED Requirements
+
+### Requirement: MCP middleware captures tool calls to buffer
+The MCP server SHALL provide injectable middleware that intercepts every tool call response and appends a structured record to `audit_buffer.jsonl` in the configured audit directory.
+
+#### Scenario: PostToolUse captures tool name and summary
+- **WHEN** any MCP tool completes execution
+- **THEN** middleware SHALL write a JSONL record with `{timestamp, tool, session, summary}` to `audit_buffer.jsonl`
+- **THEN** `tool` SHALL be the MCP tool name
+- **THEN** `summary` for Bash tools SHALL be the first non-comment command line (truncated to 200 chars)
+- **THEN** `summary` for Write/Edit tools SHALL be the file path
+
+#### Scenario: Buffer is size-limited
+- **WHEN** tool call output exceeds 1MB
+- **THEN** middleware SHALL truncate input to 1MB via `head -c 1048576` before processing
+
+#### Scenario: Buffer directory is auto-created
+- **WHEN** first tool call is captured
+- **THEN** middleware SHALL create the audit runs directory with `mkdir -p`
+
+#### Scenario: Failures do not block tool execution
+- **WHEN** buffer write fails (disk full, permission denied)
+- **THEN** middleware SHALL silently skip logging and allow the tool response to proceed
+
+### Requirement: Session flush archives buffer to trail
+The MCP middleware SHALL provide a flush mechanism that moves buffered records into session-specific audit trail files.
+
+#### Scenario: Flush moves buffer to session trail
+- **WHEN** middleware flush is triggered (on session end or explicit flush call)
+- **THEN** system SHALL read `audit_buffer.jsonl` + `audit_pending.jsonl`
+- **THEN** system SHALL concatenate them into `{session_id}/audit_trail.jsonl`
+- **THEN** system SHALL clear both buffer files
+
+#### Scenario: Auto-session for unstarted sessions
+- **WHEN** no active session exists and flush is triggered
+- **THEN** system SHALL auto-generate session ID `auto_{YYYYMMDD_HHMM}` and continue
+
+#### Scenario: Session ID via handshake file
+- **WHEN** a session is active via `/start`
+- **THEN** `{auditDir}/.current_session` SHALL contain the session ID
+- **THEN** flush SHALL read this file to determine the target session directory
+
+### Requirement: Context injection on each request
+The MCP middleware SHALL inject current session context into every incoming request's metadata.
+
+#### Scenario: Session context injected at request start
+- **WHEN** any MCP request arrives
+- **THEN** middleware SHALL add `{audit.session_id, audit.record_count, audit.status}` to the request context
+
+#### Scenario: CRITICAL alerts injected
+- **WHEN** `index.json` contains entries with `max_anomaly_level: "CRITICAL"`
+- **THEN** middleware SHALL append CRITICAL alert details to the injected context
+
+#### Scenario: Context injection is configurable
+- **WHEN** `audit.contextInjection` is set to `false`
+- **THEN** middleware SHALL skip context injection entirely