fix: Graceful HTTP client fallbacks and overflow protection

HTTP client initialization (embedding/ollama.rs, gitlab/client.rs):
- Replace expect/panic with unwrap_or_else fallback to default Client
- Log warning when configured client fails to build
- Prevents crash on TLS/system configuration issues

Doctor command (cli/commands/doctor.rs):
- Handle reqwest Client::builder() failure in Ollama health check
- Return Warning status with descriptive message instead of panicking
- Ensures doctor command remains operational even with HTTP issues

These changes improve resilience when running in unusual environments
(containers with limited TLS, restrictive network policies, etc.)
without affecting normal operation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/gitlab/client.rs

@@ -8,7 +8,7 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 use tokio::sync::Mutex;
 use tokio::time::sleep;
-use tracing::debug;
+use tracing::{debug, warn};
 
 use super::types::{
     GitLabDiscussion, GitLabIssue, GitLabIssueRef, GitLabLabelEvent, GitLabMergeRequest,
@@ -73,7 +73,13 @@ impl GitLabClient {
             .default_headers(headers)
             .timeout(Duration::from_secs(30))
             .build()
-            .expect("Failed to create HTTP client");
+            .unwrap_or_else(|e| {
+                warn!(
+                    error = %e,
+                    "Failed to build configured HTTP client; falling back to default client"
+                );
+                Client::new()
+            });
 
         Self {
             client,