We should allow specifying adjusted input annotations before csp.start / csp.alarms / csp.state

Given csp's ts[] duality in csp.node its convenient to annotate inputs as their non-ts types within the node for better IDE support.
CSP wont allow these annotations before csp.start/alarms/state blocks because csp enforces that these blocks be at the start of the method. We can / should relax this constraint to allow bare annotation lines to be declared though, since its more natural to list these up front next to the function signature

Example

import csp

@csp.node
def foo(x:csp.ts[int]):
    x : int
    with csp.start():
        s_foo = None

Leads to

Traceback (most recent call last):
  File "/home/ra7293/.config/JetBrains/PyCharm2025.2/scratches/scratch_27.py", line 3, in <module>
    @csp.node
     ^^^^^^^^
  File "/home/ra7293/user/github/csp/csp/impl/wiring/node.py", line 280, in node
    with ExceptionContext():
         ^^^^^^^^^^^^^^^^^^
  File "/home/ra7293/user/github/csp/csp/impl/error_handling.py", line 44, in __exit__
    raise exc_val.with_traceback(new_tb)
  File "/home/ra7293/.config/JetBrains/PyCharm2025.2/scratches/scratch_27.py", line 4, in <module>
    def foo(x:csp.ts[int]):
    ^^^^^^^^^^
  File "/home/ra7293/.config/JetBrains/PyCharm2025.2/scratches/scratch_27.py", line 4, in <module>
    def foo(x:csp.ts[int]):
    ^^^^^^^^^^
  File "/home/ra7293/.config/JetBrains/PyCharm2025.2/scratches/scratch_27.py", line 4, in <module>
    def foo(x:csp.ts[int]):
    ^^^^^^^^^^
csp.impl.wiring.base_parser.CspParseError: Invalid usage of start, it should appear at the beginning of the function (consult documentation for details)

The traceback points to csp/impl/wiring/node.py and csp/impl/wiring/base_parser.py; start by tracing how csp.node parses statements before csp.start, csp.alarms, and csp.state. Confirm the relevant parser tests or add coverage for the shown x: int example, with bare annotations accepted before these blocks while other ordering rules remain enforced.