Requirement Extraction
======================

Requirement extraction turns natural renter wording into ``RentalRequirements``.
The current extractor is deterministic by design. This keeps tests repeatable
and makes every rule visible to the team.

Inputs
------

* The latest customer message.
* Optional current requirements from an earlier conversation turn.
* Known locations derived from the real property cache.

Outputs
-------

* A merged ``RentalRequirements`` object.
* Confidence score.
* Notes describing what was detected.
* Missing required fields.

Common Fields
-------------

``city``
   Location detected from the real cache's known city, suburb, and region names.

``budget_max``
   Weekly budget, including phrases such as ``5k``, ``five grand``, or ``under 5000``.

``bedrooms_min``
   Minimum bedrooms requested by the renter.

``property_type``
   Normalised to values such as ``house``, ``apartment``, or ``townhouse``.

Extension Rule
--------------

When adding a new phrase, add a real-data test first or in the same commit. This
matches the Godot-style approach of making code behavior and documentation easy
for contributors to trust.