Add daily journal system (Milestone 5)

- Add journal service with date-based organization
- Add quick capture with timestamps and tags
- Add auto-linking for mentioned nodes and hashtags
- Add AI-powered daily summary generation
- Add journal search across all entries
- Add CLI commands: journal, j (alias), c (quick capture)
- Add MCP tools: memory_journal, memory_journal_list, memory_journal_summarize

src/mcp/index.ts

@@ -590,6 +590,66 @@ server.tool(
   }
 );
 
+// --- memory_journal ---
+import { getOrCreateJournal, appendToJournal, listJournals, generateJournalSummary, JournalMetadata } from '../core/journal';
+
+server.tool(
+  'memory_journal',
+  'Get or create today\'s journal, or add an entry to it',
+  {
+    text: z.string().optional().describe('Text to add to journal (if omitted, returns current journal)'),
+    date: z.string().optional().describe('Specific date (YYYY-MM-DD)'),
+    tags: z.array(z.string()).optional().describe('Tags for the entry'),
+  },
+  async ({ text, date, tags }) => {
+    if (text) {
+      const { journal, entry } = await appendToJournal(text, { tags, date });
+      const meta = journal.metadata as JournalMetadata;
+      return { content: [{ type: 'text' as const, text: serialize({ added: true, date: meta.date, entry }) }] };
+    }
+    const journal = await getOrCreateJournal(date);
+    return { content: [{ type: 'text' as const, text: serialize(journal) }] };
+  }
+);
+
+server.tool(
+  'memory_journal_list',
+  'List recent journals',
+  {
+    limit: z.number().optional().describe('Max journals to return (default: 10)'),
+    month: z.string().optional().describe('Filter by month (YYYY-MM)'),
+  },
+  async ({ limit, month }) => {
+    const journals = listJournals({ limit: limit || 10, month });
+    return {
+      content: [{
+        type: 'text' as const,
+        text: serialize(journals.map(j => {
+          const meta = j.metadata as JournalMetadata;
+          return {
+            id: j.id,
+            date: meta.date,
+            entries: meta.entries?.length || 0,
+            hasSummary: !!meta.summary,
+          };
+        })),
+      }],
+    };
+  }
+);
+
+server.tool(
+  'memory_journal_summarize',
+  'Generate AI summary for a journal',
+  {
+    date: z.string().optional().describe('Date to summarize (default: today)'),
+  },
+  async ({ date }) => {
+    const summary = await generateJournalSummary(date);
+    return { content: [{ type: 'text' as const, text: serialize({ summary }) }] };
+  }
+);
+
 // --- memory_index ---
 import { indexProject } from '../core/indexer';