fix: ChatBubble crash and DeepSeek API compatibility

- Fix ChatBubble to handle non-string content with String() wrapper
- Fix API route to use generateText for non-streaming requests
- Add @ai-sdk/openai-compatible for non-OpenAI providers (DeepSeek, etc.)
- Use Chat Completions API instead of Responses API for compatible providers
- Update ChatBubble tests and fix component exports to kebab-case
- Remove stale PascalCase ChatBubble.tsx file

_bmad-output/implementation-artifacts/gate-decision-epic-3.yaml

@@ -0,0 +1,36 @@
+traceability_and_gate:
+  traceability:
+    story_id: "Epic 3"
+    date: "2026-01-26"
+    coverage:
+      overall: 80%
+      p0: 100%
+      p1: 66%
+      p2: 75%
+      p3: 50%
+    gaps:
+      critical: 0
+      high: 4
+      medium: 2
+      low: 2
+    quality:
+      passing_tests: 0
+      total_tests: 3
+      blocker_issues: 3
+      warning_issues: 0
+    recommendations:
+      - "Run *atdd to generate missing unit/integration tests for Story 3.3"
+      - "Fix placeholder assertions in offline-action-queueing.test.ts"
+
+  gate_decision:
+    decision: "FAIL"
+    gate_type: "epic"
+    decision_mode: "deterministic"
+    criteria:
+      p0_coverage: 100%
+      p1_coverage: 66%
+      overall_coverage: 80%
+      critical_nfrs_fail: 1
+    evidence:
+      traceability: "_bmad-output/implementation-artifacts/traceability-matrix.md"
+    next_steps: "Deployment BLOCKED. Immediate remediation required for Story 3.3."