Issue #8212 : Add a Database perspective as an alternative to the SQL editor dialog

[mattcasters]

Addresses #8212.

First cut of a Database perspective as a non-modal alternative to the SQL editor dialog. This is not a DBeaver clone: no visual query builder, autocomplete, ER diagram, or grid editing. The existing modal SqlEditor and DatabaseExplorerDialog stay in place.

What this adds

• Perspective 170-HopDatabasePerspective (Ctrl+Shift+D / Cmd+Shift+D).
• Left: project DatabaseMeta tree with a filter field. Toolbar: connect, disconnect, refresh, open SQL editor, generate DDL, preview 1000 rows, show table info. Connect loads metadata in the background (JDBC is not kept open).
• Right: SQL editor tabs and table-info tabs. SQL results appear in a sash under the editor (query tabs + messages, close to hide). Long-running work is listed in an operations panel at the bottom with Kill (Statement.cancel).
• Run lives on the SQL content-editor toolbar. Ctrl+Enter / Cmd+Enter executes the selection, or the blank-line-delimited block around the caret (then split with the dialect script parser). Queries are capped at 1000 rows; timeout follows HOP_QUERY_PREVIEW_TIMEOUT.
• Open/save .sql files through the normal File menu. Explorer SQL buffers can be sent here via the database icon on the content-editor toolbar (pick a connection).
• DatabaseWorkbench is a Composite behind IDatabaseWorkbenchHost so the same UI can later float as a dialog or dock, the same way Search does.

Ctrl+Enter (GTK)

SWT StyledText treats Ctrl+Return as TRAVERSE_RETURN (shell default button) and always inserts a newline for CR even with Control held. The SQL tab listens for Traverse + KeyDown, cancels that traversal, and rejects the newline on VerifyKey / SWT.Verify. Hop Web uses Monaco CtrlCmd+Enter → executeRequested.

Out of scope (follow-ups)

• Replacing SqlEditor call sites
• Autocomplete, ER, grid edit
• Hosting the workbench as a floating dialog or bottom dock
• Opening this perspective from DatabaseExplorerDialog

Tests / docs

• SqlExecuteRangeTest, content-editor Run toolbar registration, disabled-perspective inertness
• User manual: perspective-database.adoc, perspectives list, getting-started Hop Gui

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[mattcasters]

Follow-up pushed:

Float / dock (same DatabaseWorkbench Composite as the perspective, Search-style):

• Float on the connection toolbar, or Tools → Database window, opens a non-modal window
• Dock opens a tab in the bottom dock
• One workbench instance per placement

SQL editor issues from the recent “AI Generated” reports:

• [Bug]: SQL editor fetches the whole result set — its 1000-row limit is applied client-side only #8229 — Database.getRows now calls setQueryLimit so the 1000-row cap reaches the driver (setMaxRows), not only the client read loop. Same in the new SQL tabs and the modal SqlEditor.
• [Bug]: The query timeout is not applied to DDL/DML statements #8224 — execStatement applies the statement query timeout, so HOP_QUERY_PREVIEW_TIMEOUT covers DDL/DML as well as SELECT.
• [Bug]: Database cancel-watcher threads never terminate in Hop Web — two of them are non-daemon #8228 — cancel watchers are skipped on Hop Web (no shell / Cancel button) and run as named daemon threads on desktop (DatabaseProgressCancelWatcher).

[mattcasters]

SQL from transform dialogs now opens the floating Database window instead of the modal SqlEditor.

DatabaseWorkbenchDialog.openSql(connection, sql):

1. Opens or focuses the floating workbench
2. Selects that connection and starts a background schema/table refresh
3. Puts the generated SQL in an editor tab immediately so you can edit and run (Ctrl+Enter) while the tree loads

Call sites: Table Output, Insert/Update, Update, Synchronize After Merge, SQL File Output, Dimension Lookup, Combination Lookup, and the bulk loaders (MySQL, PostgreSQL, Oracle, SQL Server native, Vertica, MonetDB, CrateDB, Snowflake, Redshift). Database explorer Open SQL / Generate DDL / Truncate uses the same path.

The modal SqlEditor class is still in the tree but no longer opened from these dialogs.

[mattcasters]

SQL editor tabs are now remembered across the perspective, floating window and bottom dock, and across Hop Gui restarts (per project, same audit store as terminal tabs).

Stored: connection, filename or unsaved buffer (capped), dirty flag, selected tab.
Not stored: query results, table-info tabs, live JDBC.

Opening Float/Dock flushes the current workbench first so the other placement restores the latest tabs.