fix(proxy): log when SOCKS5 credential auto-encoding rewrites URL (#157) (#209)

* fix(proxy): log when SOCKS5 credential auto-encoding rewrites URL (#157)

Auto URL-encoding of SOCKS5 credentials (added in v0.3.26 to fix Chromium's
'=' truncation bug) currently happens silently. Users debugging connectivity
have no way to know the wrapper rewrote their proxy URL — the original #157
thread took 8 round-trips to surface this exact ambiguity.

Emit a log when re-encoding actually changes the URL: INFO on Python's
'cloakbrowser' logger, console.debug in JavaScript. Stays silent on
already-encoded inputs and credential-less URLs to avoid false-positive
noise. Credentials are not included in the log message.

Tests: 3 new cases per language (Python caplog, JS vi.spyOn console.debug)
covering trigger / silent-when-encoded / silent-when-no-creds.

* fix(proxy): gate log on credential change, not full URL diff

Per Copilot review on #209: urlparse cosmetically lowercases scheme and
hostname, so comparing the full reconstructed URL to the input would emit
"Auto URL-encoded SOCKS5..." even for inputs like
`socks5://USER:pass@HOST.com:1080` where no credential encoding happened.

Compare raw vs encoded user/password substrings instead. Mirror the same
condition in JS for parity (JS's manual parser preserves case today, but the
credential-level compare is more robust against future changes).

Adds one regression test per language.

cloakbrowser/browser.py

@@ -813,6 +813,10 @@ def _normalize_socks_string_url(url: str) -> str:
     truncate them at special chars like '='. Idempotent: pre-encoded input stays
     the same (decoded then re-encoded).
 
+    Emits an INFO log when re-encoding actually changes the URL, so users who
+    previously hit silent SOCKS5 fallback (#157) can see what the wrapper did.
+    Silent on already-encoded inputs (no false-positive noise).
+
     On unparseable input (invalid port, broken IPv6 literal, etc.) logs a
     warning and returns the original string — preserves pre-fix pass-through
     behavior so Chromium's own error handling kicks in.
@@ -828,18 +832,30 @@ def _normalize_socks_string_url(url: str) -> str:
     # urlparse returns None for absent components, "" for present-but-empty.
     if parsed.username is None and parsed.password is None:
         return url
-    enc_user = quote(unquote(parsed.username), safe="") if parsed.username else ""
+    raw_user = parsed.username or ""
+    enc_user = quote(unquote(raw_user), safe="") if raw_user else ""
     # Preserve the colon separator when password component is present, even if
     # empty, so `user:@host` stays `user:@host`.
     if parsed.password is not None:
-        enc_pass = quote(unquote(parsed.password), safe="") if parsed.password else ""
+        raw_pass = parsed.password
+        enc_pass = quote(unquote(raw_pass), safe="") if raw_pass else ""
     else:
+        raw_pass = None
         enc_pass = None
-    return _assemble_socks_url(
+    normalized = _assemble_socks_url(
         parsed.scheme, parsed.hostname or "", parsed.port,
         enc_user, enc_pass,
         parsed.path, parsed.params, parsed.query, parsed.fragment,
     )
+    # Compare credentials, not the full URL: urlparse cosmetically lowercases
+    # scheme and hostname, so a full-string compare would falsely fire on
+    # `socks5://USER:pass@HOST.com:1080` even when no encoding work happened.
+    if enc_user != raw_user or enc_pass != raw_pass:
+        logger.info(
+            "Auto URL-encoded SOCKS5 proxy credentials (special characters "
+            "detected). Pre-encode the URL to suppress this notice."
+        )
+    return normalized
 
 
 def _extract_proxy_url(proxy: str | ProxySettings | None) -> str | None: