Add user generation feature

docs/pipeline/ROADMAP.md

@@ -33,28 +33,60 @@ architecture needs.
 - [ ] Add `BeerResult`, `CheckinResult`, `RatingResult` result payloads.
 - [ ] Add `GenerationMetadata` (`generation_id`, `generated_time`,
       `context_provided`, `generated_with`).
-- [ ] Add `activity_weight` to `UserResult` (currently just `username`,
-      `bio`).
+- [x] Add `first_name`, `last_name`, `gender`, and `activity_weight` to
+      `UserResult` (currently just `username`, `bio`). `first_name`/
+      `last_name`/`gender` are copied from the sampled `Name` (see below),
+      not LLM-invented.
+- [x] Add `Name` (`first_name`, `last_name`, `gender`) — the sampled result
+      handed to `DataGenerator::GenerateUser`. Add `ForenameEntry` (`name`,
+      `gender`) and a `NamesByCountry` class (not a bare typedef) that owns
+      two maps — `std::unordered_map<std::string, std::vector<ForenameEntry>>`
+      and `std::unordered_map<std::string, std::vector<std::string>>`, both
+      keyed by ISO 3166-1 code — and exposes `SampleName(iso3166_1, rng)`.
+      Pairing a forename with a surname happens at sample time so gender
+      (present per-forename in the source data) is never discarded the way a
+      pre-flattened `{first_name, last_name}` list would lose it; see
+      `LoadNamesByCountry()` below.
 - [ ] Extend `GeneratedBrewery` with `brewery_id`, `context_completeness`,
       `metadata` (currently just `{location, brewery}`).
-- [ ] Add `GeneratedBeer`, `GeneratedUser`, `GeneratedCheckin`,
-      `GeneratedRating`, `GeneratedFollow` aggregate structs.
-- [ ] Add `UserPersona` (`name`, `description`, `style_affinities`).
+- [ ] Add `GeneratedBeer`, `GeneratedCheckin`, `GeneratedRating`,
+      `GeneratedFollow` aggregate structs.
+- [x] Add `GeneratedUser` aggregate struct. Carries `email`, `date_of_birth`,
+      and `password` — programmatically generated by the orchestrator, never
+      LLM-authored — so a downstream auth-account seeding consumer (outside
+      this repo tree's docs) can register real accounts from the pipeline's
+      SQLite export. Skips `user_id`/`metadata` for now, matching
+      `GeneratedBrewery`'s current (pre-`brewery_id`/`metadata`) shape. Not
+      yet wired into `IExportService`/`SqliteExportService` — `GenerateUsers`
+      currently only logs and holds `generated_users_` in memory; no `users`
+      table exists in the SQLite export yet (see §5).
+- [x] Add `UserPersona` (`name`, `description`, `style_affinities`).
 
 ## 2. Data Preloading
 
 `tooling/pipeline/includes/json_handling/`, fixture files.
 
-- [ ] Extract a `DataPreloader` interface; have `JsonLoader` implement it
-      instead of exposing only a static `LoadLocations()`.
+- [ ] Extract a `DataPreloader` interface; have `JsonLoader` implement it.
+      `JsonLoader` now also exposes static `LoadPersonas()` and
+      `LoadNamesByCountry()` (see below), but as additional static methods,
+      not yet behind a formal interface.
 - [ ] Add `LoadBeerStyles()`. `beer-styles.json` already exists in the repo
       and is already copied into the Docker image
       (`runpod/Dockerfile`), but no loader reads it yet, and the native
       CMake build doesn't copy it into `build/` at all — `CMakeLists.txt`'s
       "Runtime Assets" step only copies `locations.json` and `prompts/`.
-- [ ] Add `LoadPersonas()` and author `personas.json` (doesn't exist yet).
-- [ ] Add `LoadNamesByCountry()` and author `names-by-country.json` (doesn't
-      exist yet).
+- [x] Add `LoadPersonas()` and author `personas.json` (doesn't exist yet).
+- [x] Add `LoadNamesByCountry(forenames_filepath, surnames_filepath)`,
+      parsing `tooling/pipeline/forenames-by-country.json` and
+      `surnames-by-country.json` into a `NamesByCountry`. Both files are
+      vendored verbatim (unmodified, full multinational coverage) from
+      `sigpwned/popular-names-by-country-dataset` (CC0) — see
+      ETHICS-AND-KNOWN-ISSUES.md's Names-by-Country Dataset section for
+      provenance. Deliberately not pre-paired or filtered down to just the
+      countries in `locations.json`: keeping the source shape (including
+      per-forename gender) intact means the loader can support more
+      countries later, or gender-aware persona/bio generation, without
+      re-sourcing data.
 
 ## 3. Policy / Strategy Layer
 
@@ -83,10 +115,14 @@ Entirely new — no `includes/policy/` (or equivalent) directory exists today.
 - [ ] Extend the `DataGenerator` interface with `GenerateBeer`,
       `GenerateCheckin`, `GenerateRating` (today: only `GenerateBrewery` and
       `GenerateUser`).
-- [ ] Implement `LlamaGenerator::GenerateUser` for real. It currently
-      returns a hardcoded `{"test_user", "This is a test user profile from
-    {locale}."}` regardless of input — see the `// TODO` at the top of
-      `src/data_generation/llama/generate_user.cc`.
+- [x] Implement `LlamaGenerator::GenerateUser` for real, with a retry loop
+      mirroring `GenerateBrewery` (GBNF grammar, `ValidateUserJson`, up to 3
+      attempts with corrective feedback) and a new
+      `prompts/USER_GENERATION.md`. Changed the `DataGenerator::GenerateUser`
+      signature to
+      `(city : const EnrichedCity&, persona : const UserPersona&, name : const Name&) : UserResult`,
+      matching what the activity diagram actually passes. `MockGenerator::GenerateUser`
+      updated to match the new signature too.
 - [ ] Implement `MockGenerator::GenerateBeer` / `GenerateCheckin` /
       `GenerateRating`.
 - [ ] Add `IPromptFormatter::ExpectedArchitecture()` and