feat(mysql): native SQL execution — fix #41 type decoding, in-process restore, .sql open-with (#42)

Fixes #41.

MySQL columns now decode by their declared type instead of a blind try_get chain,
so every non-string type (integers, DECIMAL, BIT, YEAR, DATE/TIME/DATETIME/TIMESTAMP)
renders its value instead of NULL. MySQL restore runs in-process over the sqlx driver
(no bundled MariaDB client, so MySQL 8 caching_sha2_password works) and the Clean toggle
is implemented. .sql files can be opened with Gridline from the OS file manager.

Verified: cargo test --lib 442 passed / 0 failed; bun run test 133 files / 1151 tests
exit 0; tsc clean; both live MySQL 8 integration tests pass with the bundled CLI hidden.

AGENTS.md

@@ -274,7 +274,7 @@ Planned work is prioritized in the [Project Roadmap](./ROADMAP.md) (source of tr
 | Connection testing (all DB types) | ✅ | PostgreSQL, MySQL, SQLite, Redis all testable |
 | DB Viewer: PostgreSQL browse + query | ✅ | Schemas, tables, paginated data, FK preview, JSON viewer |
 | DB Viewer: SQLite browse + query | ✅ | Full support via rusqlite |
-| DB Viewer: MySQL browse + query + edit | ✅ | Full viewer: connect (SSL + SSH tunnel), databases/tables/columns/FKs, query + pagination, inline cell editing + changes queue, DDL copy (`SHOW CREATE TABLE`), CSV/JSON import — added in v0.7.0. PK-only editing (no ctid equivalent); VARBINARY `information_schema` columns decoded correctly |
+| DB Viewer: MySQL browse + query + edit | ✅ | Full viewer: connect (SSL + SSH tunnel), databases/tables/columns/FKs, query + pagination, inline cell editing + changes queue, DDL copy (`SHOW CREATE TABLE`), CSV/JSON import — added in v0.7.0. PK-only editing (no ctid equivalent); VARBINARY `information_schema` columns decoded correctly. **All MySQL column types decode by their declared type** (`mysql_cell_kind` → `mysql_cell_to_json` in `commands/query.rs`, v0.8.2) — `int`/`bigint` (64-bit stringified so the value survives IPC), `decimal` (exact digits, never a float), `date`/`time`/`datetime`/`timestamp` (naive, never an instant — MySQL converts TIMESTAMP via the session time zone), `float`/`double`, `bit`, `year`, `json`, text and binary — where the previous blind `try_get` try-chain rendered every non-string type as NULL (issue #41: 21 of 30 types) |
 | DB Viewer: Redis browse | ❌ | Connection + test only; browsing gated off with a clean "not supported" state (v0.7.0) |
 | Password storage in OS keychain | ✅ | macOS Keychain, Linux Secret Service, Windows Credential Manager. macOS items get an explicit `SecAccess` ACL pinning them to the app's code-signature requirement on every save (`keychain_acl.rs`) — items survive re-signs/upgrades without keychain permission prompts. **Self-healing ACLs**: the ACL is also (silently) verified *before* reads and repaired when this app isn't in it, so items pinned to an older binary path (pre-monorepo `src-tauri/`, a reinstalled app, an ad-hoc dev build) cost one authorization instead of asking for the keychain password on every access, per secret |
 | Enable keychain toggle | ✅ | Default ON (opt-out); OFF = don't persist the DB password (session-only, re-prompt on connect) + purge existing keychain entry; SSH secrets stay keychain-only (v0.7.6) |
@@ -404,9 +404,11 @@ Planned work is prioritized in the [Project Roadmap](./ROADMAP.md) (source of tr
 | Restore UI | ✅ | In-page view: file browse, format, clean toggle, destructive confirmation checkbox, progress bar. **Clean toggle is disabled for plain format** (psql can't DROP-before-CREATE) with a hint to use Custom Archive |
 | DB-to-DB sync | ✅ | In-page view: source/target connection pickers, schema dropdown, pipe-based pg_dump → pg_restore. **pg_restore side passes `--clean --if-exists`**, so sync works into a non-empty target (UI already requires destructive-overwrite confirmation). Core logic in headless-testable `run_db_sync` |
 | Unified Tools view | ✅ | Backup / Restore / DB Sync merged into a single **Tools** nav item; operation-switcher dropdown in the view toolbar, existing forms rendered below |
-| Bundled PostgreSQL client tools | ✅ | Static pg_dump/pg_restore/psql shipped as Tauri resources; system-first, bundled-fallback resolution via resource_dir (v0.7.5) |
+| Bundled PostgreSQL client tools | ✅ | Static pg_dump/pg_restore/psql shipped as Tauri resources; system-first, bundled-fallback resolution via resource_dir (v0.7.5). `resources/mysql_tools` (mariadb-dump / mariadb) is **still bundled and still required** — for MySQL **backup** and **DB Sync** only; MySQL **restore** is native since v0.8.2 so no MySQL client is needed for it |
 | SQLite .dump (backup/restore) | ✅ | Backup a SQLite database to a portable SQL dump and restore it back, matching the pg_dump UX (v0.7.8) |
-| Backup / Restore / Sync for MySQL & SQLite | ✅ | MySQL backup/restore via mysqldump (system-first); DB-to-DB sync extended beyond PostgreSQL (v0.7.8) |
+| Backup / Restore / Sync for MySQL & SQLite | ✅ | MySQL **backup** via bundled/system `mariadb-dump` (`mysqldump`-compatible, system-first); DB-to-DB sync extended beyond PostgreSQL (v0.7.8). **MySQL restore runs in-process over the sqlx driver** (v0.8.2) — `run_mysql_restore_on` splits the script (`DELIMITER`-aware) and executes it on one connection, **no `mariadb` client and no subprocess**, so a MySQL 8 user authenticating with `caching_sha2_password` (the case the bundled client cannot reach) restores. Stop-at-first-error, cancellable, 100 MB / 1M-statement caps; MySQL **backup and DB Sync still shell out to the bundled MariaDB client** |
+| MySQL `clean` restore semantics | ✅ | `Clean` drops **only the objects the dump recreates** (`CREATE TABLE`/`VIEW`/`PROCEDURE`/`FUNCTION`/`TRIGGER`/`EVENT`), matching `pg_restore --clean` — an unrelated table in the target survives (`db/mysql_clean.rs`, v0.8.2). Deliberately not `DROP DATABASE`. The drops run with `FOREIGN_KEY_CHECKS = 0` (restored right after) so ordering cannot fail the restore. **MySQL DDL auto-commits and cannot be rolled back**, so a failure stops at the failing statement (reported with its position) and the Restore form warns that a failed restore "may leave this database partially applied" |
+| `.sql` file association (open with Gridline) | ✅ | `bundle.fileAssociations` in `tauri.conf.json` registers `.sql` as **SQL Script** (`role: Editor`, **`rank: Alternate`** — Gridline never hijacks the default handler, it only appears under *Open With*, v0.8.2). The OS path is validated (absolute, `.sql` extension, real file, ≤5 MB — `MAX_SQL_FILE_BYTES`, symlinks not followed) and queued in Rust, then drained by the **argument-free** `take_pending_sql_files` command, so the webview can never name a file to read. The text lands in a query tab named after the file and is **never executed** — Run still goes through the destructive-query guard. Re-opening the same file focuses the existing tab without discarding edits. With no connection open the file is stashed and Home shows a banner prompting for one (macOS `RunEvent::Opened`; Windows/Linux argv + single-instance forward) |
 | Schema diff / compare | ✅ | Tools → Schema Diff; same-engine snapshot diff; safe items stage into the changes queue (v0.8.0) |
 | Table structure export (DDL) | ❌ | |