chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis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/add-behavioral-engine/specs/graded-recovery/spec.md

@@ -0,0 +1,25 @@
+## ADDED Requirements
+
+### Requirement: L0 recovery (index summary)
+- **WHEN** /recover is called without arguments
+- **THEN** the last 5 index entries are loaded (~200 tokens)
+
+### Requirement: L1 recovery (session state)
+- **WHEN** /recover L1 is called
+- **THEN** current session.json + last 3 audit trail entries are loaded (~500 tokens)
+
+### Requirement: L2 recovery (user corrections)
+- **WHEN** /recover L2 is called
+- **THEN** ALL user_correction records across all sessions are loaded (~1000 tokens)
+
+### Requirement: L3 recovery (full context)
+- **WHEN** /recover L3 is called
+- **THEN** full audit trail + all pending records are loaded (~3000 tokens)
+
+### Requirement: Priority loading
+- **WHEN** recovering context
+- **THEN** user_correction records are loaded first (highest priority)
+
+#### Scenario: Session crash recovery
+- **WHEN** an agent session crashes and restarts with /recover
+- **THEN** the agent gets the index summary, last session state, and all user corrections