refactor(gemini): remove hardcoded port configuration and simplify agentapi server startup

Remove AGENTAPI_PORT parameter handling and PORT variable assignment in start script,
allowing agentapi server to use its default port. Update test name from "happy-path"
to "agent-api" for better clarity of what is being tested.

Author: DevelopmentCats

registry/coder-labs/modules/gemini/main.test.ts

@@ -70,7 +70,7 @@ describe("gemini", async () => {
     await runTerraformInit(import.meta.dir);
   });
 
-  test("happy-path", async () => {
+  test("agent-api", async () => {
     const { id } = await setup();
     await execModuleScript(id);
     await expectAgentAPIStarted(id);

registry/coder-labs/modules/gemini/scripts/start.sh

@@ -2,9 +2,6 @@
 set -o errexit
 set -o pipefail
 
-
-AGENTAPI_PORT="$2"
-
 source "$HOME"/.bashrc
 
 command_exists() {
@@ -73,6 +70,5 @@ else
     printf "No API key provided (neither GEMINI_API_KEY nor GOOGLE_API_KEY)\n"
 fi
 
-PORT=${AGENTAPI_PORT:-3284}
-agentapi server --port "$PORT" --term-width 67 --term-height 1190 -- \
+agentapi server --term-width 67 --term-height 1190 -- \
     bash -c "$(printf '%q ' gemini "${GEMINI_ARGS[@]}")"