feat(py): step 2 — per-phase latency measurement (phases.py)

Hand-drives raw sockets to time each HTTP phase individually — DNS
(getaddrinfo), TCP connect, TLS handshake (ssl.wrap_socket, https only),
TTFB (sendall → first recv), Transfer (first byte → EOF), Total.

Partial phases are preserved on failure (same invariant as Go's probe.go).
Error classification mirrors Go's priority: dns → timeout → tls → connect.
Output format matches Go's single-sample text layout.
Input: bare URL args or plain-text config file (same format as simple.py).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -4,6 +4,21 @@ All completed features are logged here in reverse-chronological order.
 
 ---
 
+## 2026-07-01 12:04 — Per-phase latency measurement (Python, Step 2)
+
+- `python/phases.py`: self-contained script; hand-drives raw sockets to time
+  each HTTP phase individually — DNS (`getaddrinfo`), TCP connect, TLS handshake
+  (`ssl.wrap_socket`, HTTPS only), TTFB (sendall → first recv), Transfer, Total
+- Partial phases preserved on failure (same invariant as Go's `probe.go`)
+- Error classification mirrors Go's priority: dns → timeout → tls → connect
+- Output format matches Go's single-sample text layout (14-char labels, `─`
+  separator, `%8.2f ms` alignment)
+- Input: bare URL args or plain-text config file (same format as `simple.py`)
+- Exits 0 if all URLs complete without network error; 1 if any failed
+- User doc: `docs/usage/py-phases.md`
+
+---
+
 ## 2026-07-01 11:30 — Error-path example configs for simple.py (Python, Step 1 refinement)
 
 - `python/configs/` directory with 7 purpose-built config files, one per error class: