feat(roadmap): YAML-driven roadmap + Tailwind UI w/ filters & details modal

- Convert roadmap to YAML:
  - Add data structure: id, priority, title, goal, tags, milestone
  - Add `details` field (supports list or block string); populated initial content
  - Quote scalars and use explicit nulls to avoid YAML parse edge cases
  - Update `updated` date to 2025-08-22

- Flask blueprint + loader:
  - New /roadmap view with section switching (roadmap | backlog | open_questions)
  - Filters: q (search), tag (multi, AND), min_priority, milestone
  - Dataclasses: RoadmapData/RoadmapItem; include `details`
  - `_normalize_details()` to accept string or list, normalize to list[str]
  - Configurable path via `ROADMAP_FILE` (env or defaults)
  - Remove cache layer for simplicity

- UI (Tailwind):
  - `templates/roadmap.html` with responsive cards, tag chips, and filter form
  - Details modal (larger max width, scrollable body) showing ID/goal/priority/tags/milestone
  - Safe JSON payload to modal via `|tojson|forceescape`

- JS:
  - DOM-ready, event-delegated handler for `data-item` buttons
  - Populate modal fields and render multi-paragraph details

- Fixes & polish:
  - Resolved YAML `ScannerError` by quoting strings with `:` and `#`
  - Ensured `details` is passed through route to template and included in button payload
  - Minor styling tweaks for consistency with Tailwind setup

Usage:
- Set `ROADMAP_FILE` if not using default path
- Visit /roadmap and filter via q/tag/min_priority/milestone

app/__init__.py

@@ -7,8 +7,9 @@ from flask import Flask
 from .utils.settings import get_settings
 from .logging_setup import wire_logging_once, get_app_logger, get_engine_logger
 
-from app.blueprints import ui  # ui blueprint
-from app.blueprints import api  # api blueprint
+from app.blueprints.ui import bp as main_bp  # ui blueprint
+from app.blueprints.api import api_bp as api_bp  # api blueprint
+from app.blueprints.roadmap import bp as roadmap_bp # roadmap
 
 def create_app() -> Flask:
     """
@@ -41,9 +42,14 @@ def create_app() -> Flask:
     app.config["APP_NAME"] = settings.app.name
     app.config["APP_VERSION"] = f"v{settings.app.version_major}.{settings.app.version_minor}"
 
+    # roadmap file
+    app.config["ROADMAP_FILE"] = str(Path(app.root_path) / "docs" / "roadmap.yaml")
+
+
     # Register blueprints
-    app.register_blueprint(ui.bp)
-    app.register_blueprint(api.api_bp)
+    app.register_blueprint(main_bp)
+    app.register_blueprint(api_bp)
+    app.register_blueprint(roadmap_bp)
 
     app_logger = get_app_logger()