Fix: Adjust LLM token budget and navigation flow

Increase `max_completion_tokens` for `gpt_oss_120b` from 8192 to 16384
to prevent incomplete responses.

Navigate to the detail screen before the recording screen when starting
a new case, ensuring correct back navigation.

server/src/analyze/backend.rs

@@ -157,14 +157,15 @@ pub fn backends() -> &'static [LlmBackend] {
             // gpt-oss-120b: schema OFF on purpose. Reasoning tokens count
             // against `max_completion_tokens`; with `high` reasoning the
             // CoT alone can eat several thousand tokens, so the budget is
-            // doubled to 8192 to leave room for the actual answer. Without
-            // headroom the model returns `choices[0].message.content == null`
+            // raised to 4x the default to leave room for the actual answer.
+            // Without headroom the model returns
+            // `choices[0].message.content == null` (finish_reason="length")
             // — the LlmError::Parse path. Pre-multi-backend (commit bf6464d)
             // gpt-oss ran without schema and worked fine; this restores
             // that body byte-for-byte except for the larger budget.
             ionos_backend("gpt_oss_120b", "GPT OSS 120b", "openai/gpt-oss-120b")
                 .with_reasoning_effort("high")
-                .with_max_completion_tokens(8192)
+                .with_max_completion_tokens(16384)
                 .with_use_json_schema(false),
             ionos_backend(
                 "llama_3_1_405b",