feat(coder): add LSP code intelligence tools

- lsp/ module: types, config, JSON-RPC client, server-manager, operations
- lsp_diagnostics: TypeScript/JavaScript diagnostics for a file
- lsp_goto_definition: find symbol definition at position
- lsp_find_references: find all references to a symbol
- Registered as READ_TOOLS in tool index

apps/coder/src/services/lsp/server-manager.ts

@@ -0,0 +1,119 @@
+import { spawn, type ChildProcess } from 'node:child_process';
+import { join } from 'node:path';
+import { existsSync } from 'node:fs';
+import { LspClient } from './client.js';
+import { getServerConfig } from './config.js';
+
+const IDLE_TIMEOUT_MS = 5 * 60 * 1000;
+const SWEEP_INTERVAL_MS = 30_000;
+
+interface LspInstance {
+  client: LspClient;
+  proc: ChildProcess;
+  lastUsed: number;
+  timer: ReturnType<typeof setTimeout>;
+}
+
+export class LspServerManager {
+  private instances = new Map<string, LspInstance>();
+  private sweepTimer: ReturnType<typeof setInterval> | null = null;
+
+  constructor() {
+    this.startSweeper();
+  }
+
+  private startSweeper(): void {
+    this.sweepTimer = setInterval(() => this.sweep(), SWEEP_INTERVAL_MS);
+    this.sweepTimer.unref?.();
+  }
+
+  private findProjectRoot(filePath: string): string | null {
+    let dir = filePath;
+    const config = getServerConfig(filePath);
+    if (!config) return null;
+    while (true) {
+      for (const pattern of config.rootPatterns) {
+        if (existsSync(join(dir, pattern))) return dir;
+      }
+      const parent = join(dir, '..');
+      if (parent === dir) return dir;
+      dir = parent;
+    }
+  }
+
+  async getClient(filePath: string): Promise<LspClient | null> {
+    const config = getServerConfig(filePath);
+    if (!config) return null;
+    const projectRoot = this.findProjectRoot(filePath);
+    if (!projectRoot) return null;
+
+    const existing = this.instances.get(projectRoot);
+    if (existing) {
+      existing.lastUsed = Date.now();
+      clearTimeout(existing.timer);
+      existing.timer = setTimeout(() => this.kill(projectRoot), IDLE_TIMEOUT_MS);
+      existing.timer.unref?.();
+      return existing.client;
+    }
+
+    return this.spawn(projectRoot, config.command, config.args);
+  }
+
+  private async spawn(projectRoot: string, command: string, args: string[]): Promise<LspClient> {
+    const proc = spawn(command, args, { stdio: ['pipe', 'pipe', 'pipe'], cwd: projectRoot });
+    const client = new LspClient(proc.stdin!, proc.stdout!);
+
+    await client.request('initialize', {
+      processId: process.pid,
+      rootUri: `file://${projectRoot}`,
+      capabilities: {
+        textDocument: {
+          diagnostic: { dynamicRegistration: false },
+          definition: { dynamicRegistration: false },
+          references: { dynamicRegistration: false },
+        },
+      },
+    });
+    await client.notify('initialized', {});
+
+    const timer = setTimeout(() => this.kill(projectRoot), IDLE_TIMEOUT_MS);
+    timer.unref?.();
+
+    this.instances.set(projectRoot, { client, proc, lastUsed: Date.now(), timer });
+    proc.on('exit', () => this.instances.delete(projectRoot));
+
+    return client;
+  }
+
+  private kill(projectRoot: string): void {
+    const inst = this.instances.get(projectRoot);
+    if (!inst) return;
+    this.instances.delete(projectRoot);
+    inst.proc.kill('SIGTERM');
+    setTimeout(() => {
+      if (inst.proc.exitCode === null) inst.proc.kill('SIGKILL');
+    }, 5000);
+  }
+
+  private sweep(): void {
+    const now = Date.now();
+    for (const [root, inst] of this.instances) {
+      if (now - inst.lastUsed > IDLE_TIMEOUT_MS) {
+        this.kill(root);
+      }
+    }
+  }
+
+  shutdown(): void {
+    if (this.sweepTimer) clearInterval(this.sweepTimer);
+    for (const root of [...this.instances.keys()]) {
+      this.kill(root);
+    }
+  }
+
+  getActiveCount(): number {
+    return this.instances.size;
+  }
+}
+
+export const lspManager = new LspServerManager();