Add context injection system (Milestone 3)

- Add src/core/context.ts with context gathering, ranking, and formatting
- Add src/core/config.ts for persistent configuration storage
- Add CLI commands: cortex context, cortex context-hook, cortex config
- Add memory_context MCP tool for Claude Code integration
- Add GET /api/context endpoint
- Include summary.ts from main branch for heartbeat dependency

src/cli/commands/config.ts

@@ -0,0 +1,81 @@
+import { Command } from 'commander';
+import chalk from 'chalk';
+import { getConfig, setConfig, listConfig, resetConfig, CortexConfig } from '../../core/config';
+
+export const configCommand = new Command('config')
+  .description('Manage Cortex configuration');
+
+configCommand
+  .command('get <key>')
+  .description('Get a config value')
+  .action((key: string) => {
+    try {
+      const value = getConfig(key as keyof CortexConfig);
+      console.log(value);
+    } catch (err) {
+      console.error(chalk.red(`Unknown config key: ${key}`));
+      process.exit(1);
+    }
+  });
+
+configCommand
+  .command('set <key> <value>')
+  .description('Set a config value')
+  .action((key: string, value: string) => {
+    // Validate key exists
+    const validKeys = [
+      'context.maxTokens',
+      'context.maxNodes',
+      'context.includeRecent',
+      'context.includeProject',
+      'context.includeTasks',
+      'context.includeDecisions',
+    ];
+
+    if (!validKeys.includes(key)) {
+      console.error(chalk.red(`Unknown config key: ${key}`));
+      console.error(chalk.dim(`Valid keys: ${validKeys.join(', ')}`));
+      process.exit(1);
+    }
+
+    // Parse value based on key type
+    let parsed: string | number | boolean = value;
+    if (key.startsWith('context.max')) {
+      parsed = parseInt(value, 10);
+      if (isNaN(parsed)) {
+        console.error(chalk.red(`Invalid number: ${value}`));
+        process.exit(1);
+      }
+    } else if (key.startsWith('context.include')) {
+      if (value !== 'true' && value !== 'false') {
+        console.error(chalk.red(`Invalid boolean: ${value} (use true or false)`));
+        process.exit(1);
+      }
+      parsed = value === 'true';
+    }
+
+    setConfig(key as keyof CortexConfig, parsed as any);
+    console.log(chalk.green(`Set ${key} = ${parsed}`));
+  });
+
+configCommand
+  .command('list')
+  .description('List all config values')
+  .action(() => {
+    const configs = listConfig();
+    console.log(chalk.bold('Configuration:'));
+    console.log();
+
+    for (const { key, value, isDefault } of configs) {
+      const displayValue = isDefault ? chalk.dim(`${value} (default)`) : chalk.cyan(value);
+      console.log(`  ${chalk.yellow(key)}: ${displayValue}`);
+    }
+  });
+
+configCommand
+  .command('reset <key>')
+  .description('Reset a config key to default')
+  .action((key: string) => {
+    resetConfig(key as keyof CortexConfig);
+    console.log(chalk.green(`Reset ${key} to default`));
+  });

src/cli/commands/context.ts

@@ -0,0 +1,85 @@
+import { Command } from 'commander';
+import chalk from 'chalk';
+import * as path from 'path';
+import { gatherContext, DEFAULT_CONTEXT_CONFIG } from '../../core/context';
+
+export const contextCommand = new Command('context')
+  .description('Preview or inject context for a Claude session')
+  .option('-p, --project <name>', 'Project name (defaults to current directory name)')
+  .option('-q, --query <text>', 'Additional semantic search query')
+  .option('--max-tokens <n>', 'Maximum tokens', String(DEFAULT_CONTEXT_CONFIG.maxTokens))
+  .option('--max-nodes <n>', 'Maximum nodes', String(DEFAULT_CONTEXT_CONFIG.maxNodes))
+  .option('--format <fmt>', 'Output format: markdown or json', 'markdown')
+  .option('--no-recent', 'Exclude recent activity')
+  .option('--no-tasks', 'Exclude open tasks')
+  .option('--no-decisions', 'Exclude decisions')
+  .action(async (opts) => {
+    const project = opts.project ?? path.basename(process.cwd());
+
+    const result = await gatherContext({
+      project,
+      semanticQuery: opts.query,
+      config: {
+        maxTokens: parseInt(opts.maxTokens),
+        maxNodes: parseInt(opts.maxNodes),
+        includeRecent: opts.recent !== false,
+        includeTasks: opts.tasks !== false,
+        includeDecisions: opts.decisions !== false,
+      },
+    });
+
+    if (opts.format === 'json') {
+      console.log(JSON.stringify({
+        project,
+        nodeCount: result.nodes.length,
+        nodes: result.nodes.map(r => ({
+          id: r.node.id,
+          kind: r.node.kind,
+          title: r.node.title,
+          score: r.score,
+          reason: r.reason,
+        })),
+      }, null, 2));
+      return;
+    }
+
+    // Markdown output
+    if (result.nodes.length === 0) {
+      console.log(chalk.yellow('No relevant context found.'));
+      return;
+    }
+
+    console.log(chalk.cyan(`# Context for ${project}`));
+    console.log(chalk.dim(`(${result.nodes.length} nodes)`));
+    console.log();
+    console.log(result.formatted);
+  });
+
+/**
+ * Hook command for Claude Code integration
+ * Outputs context to stdout for injection
+ */
+export const contextHookCommand = new Command('context-hook')
+  .description('Hook handler for Claude Code session start (outputs context to stdout)')
+  .option('-p, --project <name>', 'Project name (defaults to current directory name)')
+  .option('--max-tokens <n>', 'Maximum tokens', String(DEFAULT_CONTEXT_CONFIG.maxTokens))
+  .action(async (opts) => {
+    const project = opts.project ?? path.basename(process.cwd());
+
+    const result = await gatherContext({
+      project,
+      config: {
+        maxTokens: parseInt(opts.maxTokens),
+      },
+    });
+
+    if (result.nodes.length === 0) {
+      // Output nothing if no context
+      return;
+    }
+
+    // Output markdown directly to stdout for Claude to consume
+    console.log(`<cortex-context project="${project}">`);
+    console.log(result.formatted);
+    console.log('</cortex-context>');
+  });

src/cli/index.ts

@@ -11,6 +11,8 @@ import { graphCommand } from './commands/graph';
 import { serveCommand } from './commands/serve';
 import { decayCommand } from './commands/decay';
 import { childrenCommand } from './commands/children';
+import { contextCommand, contextHookCommand } from './commands/context';
+import { configCommand } from './commands/config';
 import { closeDb } from '../core/db';
 
 const program = new Command();
@@ -31,6 +33,9 @@ program.addCommand(graphCommand);
 program.addCommand(serveCommand);
 program.addCommand(decayCommand);
 program.addCommand(childrenCommand);
+program.addCommand(contextCommand);
+program.addCommand(contextHookCommand);
+program.addCommand(configCommand);
 
 program.hook('postAction', () => {
   closeDb();