refactor(paths): replace 26 modules hardcoded ~/.pry/ with PRY_DATA_DIR

Each module did:
    X_DIR = Path(os.path.expanduser("~/.pry/x"))

After:
    from paths import PRY_DATA_DIR
    X_DIR = PRY_DATA_DIR / "x"

The module-level Path construction is preserved, so the rest of the
code is unchanged. PRY_DATA_DIR is read once at import (overridable via
the env var of the same name).

Verified:
- 407 tests collect (was 5 collection errors from a misplaced import)
- 83 sampled tests pass (intelligence, proxy_manager, x402, agency,
  gdpr, referrals, marketplace, api)
- 0 remaining hardcoded ~/.pry references in .py files

Follow-up: paths.py adds subdir(name) helper for new code that wants
auto-mkdir; existing modules still call .mkdir(exist_ok=True) themselves
to preserve the eager-init behavior they had before.

proxy_manager.py

@@ -1,6 +1,7 @@
 """Pry — Proxy Manager with affiliate-signup flow.
 Tries free proxies first (Tor, public rotating). When premium proxy is needed,
 prompts user to sign up via affiliate links. Pre-wired to 5+ providers."""
+from paths import PRY_DATA_DIR
 
 # SPDX-License-Identifier: MIT
 # Copyright (c) 2026 Rug Munch Media LLC
@@ -24,7 +25,7 @@ try:
 except ImportError:  # proxy_referrals module not always present in slim installs
     _PROXY_REFERRALS = {}
 
-PROXY_DIR = Path(os.path.expanduser("~/.pry/proxies"))
+PROXY_DIR = PRY_DATA_DIR / "proxies"
 PROXY_DIR.mkdir(parents=True, exist_ok=True)
 
 # Free proxy sources (no signup required)