[SizzleUnrlsd]

Summary

The two frameworks left open on #30, done as model plugins plus two small, generic engine mechanisms.

• Acceptance tests first (test: define Django and HTTP client model behavior), implementation follows.
• Parameter.annotation in the PyHIR: kept when the annotation is an expression the HIR represents, dropped otherwise, so no file that parsed before fails now.
• TypedParameter model: a parameter annotated with the model's class symbol is attacker-controlled. Annotations resolve through the symbol table, so aliases such as http.HttpRequest work.
• EntryPoint now also applies to the methods of a class deriving from its symbol, self excluded. taint.engine.parameter_sources gathers the three origins (decorators, bases, annotations) into per-parameter sources; propagate_taint takes that mapping instead of one entry point.
• models/django: request classes as typed parameters (Django and Django REST framework), class-based view bases and view decorators as entry points, raw cursor, RawSQL, raw/extra SQL sinks, mark_safe/HttpResponse/Template HTML sinks, FileResponse path sink, escape/conditional_escape sanitizers. A bare request parameter without annotation, base or decorator is not recognised and URL configurations are not read; both are documented.
• models/http_clients: every Requests and httpx request function, on the module, on Session, Client and AsyncClient, is a SSRF sink, and its result an http-response source, so data fetched from a remote server is untrusted downstream.
• Detectors unchanged.

Closes #30