refactor(pipeline): restructure config, add PromptDirectory, consolidate SQLite layer (#217)

* Refactor ApplicationOptions to separate config concerns

* add prompt dir app option

* readability updates: remove magic numbers, update comments

* codebase formatting

* Update docs

* Extract argument parsing, timer out of

tooling/pipeline/src/data_generation/llama/generate_user.cc

@@ -12,6 +12,13 @@
 #include "data_generation/llama_generator.h"
 #include "data_generation/llama_generator_helpers.h"
 
+// TODO: Implement locale-aware user profile generation.
+// Current implementation returns a hardcoded test value and ignores the
+// locale parameter. Future implementation should:
+// 1. Load a USER_GENERATION.md prompt template with locale context
+// 2. Perform LLM inference with locale-specific username/bio generation
+// 3. Parse and validate JSON output with retry handling (similar to brewery)
+// 4. Return locale-aware username and biography
 UserResult LlamaGenerator::GenerateUser(const std::string& locale) {
   return {.username = "test_user",
           .bio = "This is a test user profile from " + locale + "."};