feat(memory): implement persistent project-level Knowledge Graph and RAG (#899)

- Shift memory from session-scope to persistent project-scope\n- Add native JSON RAG with BM25-lite ranking\n- Implement passive technical concept extraction (IPs, versions, frameworks)\n- Orchestrate hierarchical context injection in the conversation loop

src/commands/knowledge/knowledge.test.ts

@@ -2,9 +2,15 @@ import { describe, expect, it, beforeEach } from 'bun:test'
 import { call as knowledgeCall } from './knowledge.js'
 import { getGlobalConfig, saveGlobalConfig } from '../../utils/config.js'
 import { getArc, addEntity, resetArc } from '../../utils/conversationArc.js'
+import { getGlobalGraph, resetGlobalGraph } from '../../utils/knowledgeGraph.js'
 
 describe('knowledge command', () => {
   const mockContext = {} as any
+
+  beforeEach(() => {
+    resetArc()
+    resetGlobalGraph()
+  })
   
   const knowledgeCallWithCapture = async (args: string) => {
     const result = await knowledgeCall(args, mockContext)
@@ -51,12 +57,13 @@ describe('knowledge command', () => {
   it('clears the knowledge graph', async () => {
     // Add a fact first
     addEntity('test', 'fact')
-    const arc = getArc()
-    expect(Object.keys(arc!.knowledgeGraph.entities).length).toBe(1)
+    const graph = getGlobalGraph()
+    expect(Object.keys(graph.entities).length).toBe(1)
 
     // Clear it
     const res = await knowledgeCallWithCapture('clear')
-    expect(Object.keys(getArc()!.knowledgeGraph.entities).length).toBe(0)
+    const graphAfter = getGlobalGraph()
+    expect(Object.keys(graphAfter.entities).length).toBe(0)
     expect(res.toLowerCase()).toContain('cleared')
   })
 

src/commands/knowledge/knowledge.ts

@@ -1,5 +1,6 @@
 import type { LocalCommandCall } from '../../types/command.js';
-import { getArcSummary, resetArc, getArcStats, getArc } from '../../utils/conversationArc.js';
+import { getArcSummary, resetArc, getArcStats } from '../../utils/conversationArc.js';
+import { getGlobalGraph, resetGlobalGraph } from '../../utils/knowledgeGraph.js';
 import { getGlobalConfig, saveGlobalConfig } from '../../utils/config.js';
 import chalk from 'chalk';
 
@@ -11,8 +12,8 @@ export const call: LocalCommandCall = async (args, _context) => {
   if (!subCommand || subCommand === 'status') {
     const config = getGlobalConfig();
     const stats = getArcStats();
-    const arc = getArc();
-    const entityCount = Object.keys(arc?.knowledgeGraph.entities || {}).length;
+    const graph = getGlobalGraph();
+    const entityCount = Object.keys(graph.entities).length;
     
     const statusText = (config.knowledgeGraphEnabled !== false)
       ? chalk.green('ENABLED') 
@@ -44,6 +45,7 @@ export const call: LocalCommandCall = async (args, _context) => {
 
   if (subCommand === 'clear') {
     resetArc();
+    resetGlobalGraph();
     return { 
       type: 'text', 
       value: '🗑️ Knowledge graph memory has been cleared for this session.'