coder(providers): capture + persist opencode's live ACP commands (no dispatch needed)

The cold ACP probe captured available_commands but read probedCommands synchronously right after newSession, racing opencode's async available_commands_update notification -> captured nothing, only the static manifest showed. The probe now waits (poll <=3s + 300ms settle) for the notification. Captured commands persist to a new available_agents.commands column and are served (merged with the manifest) on the tier-2-skip path, so the agent's discovered commands survive once models are warm and show without a dispatch. Boot warms via the force:true startup snapshot. Caveat: relies on opencode emitting available_commands_update on session creation, not only post-prompt.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/coder/src/services/acp-probe.ts

@@ -130,6 +130,17 @@ export async function probeAcpProvider(
     });
 
     const session = await connection.newSession({ cwd, mcpServers: [] });
+    // available_commands_update is an async session notification opencode sends
+    // shortly AFTER newSession resolves — reading probedCommands synchronously
+    // here races it and captures nothing. Wait briefly for the first batch, then
+    // a short settle for any stragglers (capped well under PROBE_TIMEOUT_MS).
+    const deadline = Date.now() + 3_000;
+    while (probedCommands.length === 0 && Date.now() < deadline) {
+      await new Promise((r) => setTimeout(r, 150));
+    }
+    if (probedCommands.length > 0) {
+      await new Promise((r) => setTimeout(r, 300));
+    }
     const result = parseSessionResponse(session, agent);
     result.commands = probedCommands;
     await connection.closeSession({ sessionId: session.sessionId }).catch(() => {});