fix: connect() orphan (lockstep psql-3) + await pool.release() (mysql-1)

- connect() closes an existing pool on re-connect and tears down the built pool on SELECT-1
  validation failure (sibling of psql-3).
- _Transaction now awaits pool.release() in both __aexit__ and the __aenter__ failure path,
  matching psql and aiomysql's idiom (no un-awaited _wakeup task per transaction).
- README: insert-returns-lastrowid headline precision + upsert-rowcount convention note.
verified vs real MariaDB (re-connect, 5-tx release, full suite). bump v0.1.1 -> v0.1.2

Signed-off-by: disqualifier <dev@disqualifier.me>

README.md

@@ -11,24 +11,26 @@ wire-compatible and share the driver, so this covers both.
 `requirements.txt`:
 
 ```
-mysql @ git+ssh://git@git.rethinkstudios.io/rethink-public/mysql.git@v0.1.1
+mysql @ git+ssh://git@git.rethinkstudios.io/rethink-public/mysql.git@v0.1.2
 ```
 
 Direct:
 
 ```bash
-pip install "mysql @ git+ssh://git@git.rethinkstudios.io/rethink-public/mysql.git@v0.1.1"
+pip install "mysql @ git+ssh://git@git.rethinkstudios.io/rethink-public/mysql.git@v0.1.2"
 ```
 
 Pulls `aiomysql` (which pulls `PyMySQL`).
 
-Drop the `@v0.1.1` suffix from the line above to install the latest unpinned.
+Drop the `@v0.1.2` suffix from the line above to install the latest unpinned.
 
 ## The two-layer API
 
 **Layer 1 — friendly verbs** for simple single-table CRUD. These hide the dialect and are
-**identical to the `psql` lib** — same method names, signatures, return shapes — so you
-swap psql↔mysql with zero call-site changes.
+**signature-identical to the `psql` lib** — same method names, arguments, and return
+*types* — so you swap psql↔mysql with zero call-site changes. One value-level difference:
+`insert()` returns the new row id (`lastrowid`) here vs. the inserted rowcount in psql
+(both `int`); everything else returns the same shape.
 
 **Layer 2 — raw escape hatch** for the complex ~20% (joins, aggregates, subqueries). You
 write the SQL with `%s` placeholders + a params sequence; the wrapper still gives pooling,
@@ -111,6 +113,10 @@ Layer 1 is portable — you never see these. A Layer-2 raw-SQL author does:
 `fetchone` is the unified Layer-2 name in both libs (psql maps it onto asyncpg's
 `fetchrow` internally; here it's the native DBAPI verb).
 
+`upsert()`'s returned rowcount follows MySQL's `ON DUPLICATE KEY UPDATE` convention (1 for
+an insert, 2 for an update, 0 for a no-op) — a per-row count that differs from psql's; treat
+it as "affected", not "rows matched".
+
 ## Error contract — fail loud
 
 Unlike the `mongo` lib (which log-and-swallows), **this lib re-raises.** Every method