Add wrapped_self() — Phase 1 fix for #18 (self is unwrapped in delegation-wrapped stores)

[thorwhalen]

What

Adds wrapped_self() — the Phase-1, backward-compatible fix for #18. dol wraps by delegation (has-a), so a method defined on a wrap_kvs-decorated class runs bound to the inner, unwrapped store; self[k] inside it bypasses the transform pipeline. wrapped_self(self)[k] recovers the outer, transform-applying store.

from dol import wrap_kvs, wrapped_self

@wrap_kvs(data_of_obj=lambda x: x*x, obj_of_data=lambda x: math.sqrt(x))
class S(dict):
    def via_self(self, k):          return self[k]                  # #18: returns raw (4)
    def via_wrapped_self(self, k):  return wrapped_self(self)[k]    # transformed (2.0)

How

• id-keyed weakref registry populated once in Store.__init__ (covers class- and instance-wraps) and re-populated in Store.__setstate__ (unpickle bypasses __init__); guarded compare-and-pop finalizer.
• Climbs to the outermost wrapper for stacked/Pipe wraps; safe no-op on direct Store subclasses and plain objects.
• Does not touch DelegatedAttribute.__get__, the delegate_to copy loop, or the base.py:451 signature graft.

Why this design (not method-rebinding)

A full analysis of 4 approaches (+ adversarial review + empirical verification) is in misc/docs/dol_issue18_design.md (docs PR). Rebinding self to the wrapper was rejected: under Pipe/stacked wraps it binds to the innermost layer (silent write corruption) and crashes on super()/dict-native ops. wrapped_self avoids all of that and uniquely covers the instance-wrap path. The structural fix (is-a wrapping, which would also close #6) is deferred to a major version.

Safety

• Zero default behavior change (additive; registry writes only).
• Dependents test-gate (top 15): 0 PASS→FAIL. The 3 non-passing dependents (hubcap, msword, raglab-bak) fail identically at baseline (pre-existing collection/import errors, unrelated).
• Full dol suite green; 7 regression tests (single-layer, nested climb, instance-wrap, pickle round-trip, direct-subclass no-op, plain-object no-op, zero-behavior-change) + a runnable doctest.

Refs #18

https://claude.ai/code/session_01H8PmV6xmMhzV64zi1Twraw