config: add auto-compact settings for Claude and Codex agents

Claude: CLAUDE_AUTOCOMPACT_PCT_OVERRIDE=50 (~500K on 1M context)
Codex: model_auto_compact_token_limit=258000 (matching CLI default)

src/env.ts

@@ -2,13 +2,12 @@ import fs from 'fs';
 import path from 'path';
 import { logger } from './logger.js';
 
-/**
- * Parse the .env file and return values for the requested keys.
- * Does NOT load anything into process.env — callers decide what to
- * do with the values. This keeps secrets out of the process environment
- * so they don't leak to child processes.
- */
-export function readEnvFile(keys: string[]): Record<string, string> {
+// ── Internal cache ──────────────────────────────────────────────
+
+let _cache: Record<string, string> | null = null;
+
+/** Parse the entire .env file into a Record (no key filtering). */
+function parseEnvFile(): Record<string, string> {
   const envFile = path.join(process.cwd(), '.env');
   let content: string;
   try {
@@ -19,15 +18,12 @@ export function readEnvFile(keys: string[]): Record<string, string> {
   }
 
   const result: Record<string, string> = {};
-  const wanted = new Set(keys);
-
   for (const line of content.split('\n')) {
     const trimmed = line.trim();
     if (!trimmed || trimmed.startsWith('#')) continue;
     const eqIdx = trimmed.indexOf('=');
     if (eqIdx === -1) continue;
     const key = trimmed.slice(0, eqIdx).trim();
-    if (!wanted.has(key)) continue;
     let value = trimmed.slice(eqIdx + 1).trim();
     if (
       (value.startsWith('"') && value.endsWith('"')) ||
@@ -37,6 +33,46 @@ export function readEnvFile(keys: string[]): Record<string, string> {
     }
     if (value) result[key] = value;
   }
-
+  return result;
+}
+
+// ── Public API ──────────────────────────────────────────────────
+
+/** Load (or reload) the .env file into the in-memory cache. */
+export function loadEnvFile(): void {
+  _cache = parseEnvFile();
+}
+
+/**
+ * Look up a single env value.
+ * Priority: process.env > .env cache > undefined
+ */
+export function getEnv(key: string): string | undefined {
+  if (!_cache) loadEnvFile();
+  return process.env[key] || _cache![key] || undefined;
+}
+
+/** Force-reload the .env file (e.g. after token refresh writes new values). */
+export function reloadEnvFile(): void {
+  _cache = null;
+  loadEnvFile();
+}
+
+/**
+ * Parse the .env file and return values for the requested keys.
+ * Does NOT load anything into process.env — callers decide what to
+ * do with the values. This keeps secrets out of the process environment
+ * so they don't leak to child processes.
+ *
+ * Now backed by the in-memory cache (disk read happens at most once).
+ */
+export function readEnvFile(keys: string[]): Record<string, string> {
+  if (!_cache) loadEnvFile();
+
+  const result: Record<string, string> = {};
+  const wanted = new Set(keys);
+  for (const [key, value] of Object.entries(_cache!)) {
+    if (wanted.has(key)) result[key] = value;
+  }
   return result;
 }