Fix python f-string backslash syntax compatibility

BACKERS.md

@@ -0,0 +1,6 @@
+# Backers
+
+Thank you to all our backers who support the development of this curriculum!
+
+## Backers List
+*(No backers listed yet)*

ROADMAP.md

@@ -4,7 +4,7 @@ Status tracker for every phase and lesson. The status glyphs in this file feed
 the website (`site/build.js` parses them into `site/data.js`); do not change
 their shape.
 
-Total estimated time: ~314 hours, at your own pace.
+Total estimated time: ~950 hours, at your own pace.
 
 **Legend:** ✅ Complete  ·  🚧 In Progress  ·  ⬚ Planned
 
@@ -264,7 +264,7 @@ Total estimated time: ~314 hours, at your own pace.
 | 21 | [Jamba — Hybrid SSM-Transformer](phases/10-llms-from-scratch/21-jamba-hybrid-ssm-transformer) | ✅ | ~60 min |
 | 22 | [Async and Hogwild! Inference](phases/10-llms-from-scratch/22-async-hogwild-inference) | ✅ | ~60 min |
 
-## Phase 11: LLM Engineering — ✅ (~17 hours)
+## Phase 11: LLM Engineering — ✅ (~19 hours)
 
 | # | Lesson | Status | Est. |
 |---|--------|--------|------|
@@ -283,6 +283,8 @@ Total estimated time: ~314 hours, at your own pace.
 | 13 | [Building a Production LLM Application](phases/11-llm-engineering/13-production-app) | ✅ | ~120 min |
 | 14 | [Model Context Protocol (MCP)](phases/11-llm-engineering/14-model-context-protocol) | ✅ | ~75 min |
 | 15 | [Prompt Caching & Context Caching](phases/11-llm-engineering/15-prompt-caching) | ✅ | ~60 min |
+| 16 | [LangGraph: State Machines for Agents](phases/11-llm-engineering/16-langgraph-state-machines) | ✅ | ~75 min |
+| 17 | [Agent Framework Tradeoffs](phases/11-llm-engineering/17-agent-framework-tradeoffs) | ✅ | ~45 min |
 
 ## Phase 12: Multimodal AI — ✅ (~65 hours)
 

phases/05-nlp-foundations-to-advanced/28-long-context-evaluation/code/main.py

@@ -56,7 +56,7 @@ def run_niah_grid(lengths, depths, seed=0):
     needle = "the magic word is pineapple"
     expected = "pineapple"
     capacity = 20000
-    print(f"  {'depth\\len':<12}  " + "  ".join(f"{n:>6}" for n in lengths))
+    print("  {:<12}  ".format("depth\\len") + "  ".join(f"{n:>6}" for n in lengths))
     for d in depths:
         row = []
         for n in lengths:

site/data.js

@@ -1,5 +1,5 @@
 // Auto-generated by build.js — do not edit manually.
-// Last built: 2026-05-25T10:54:44.943Z
+// Last built: 2026-05-25T15:23:28.325Z
 
 const PHASES = [
   {