[datlechin]

Summary

• One DataGrid widget (ui/data_grid) replaces ui/grid on every surface: table tabs, SQL results and key tabs. It owns selection, keys, menus, editing, copy, find and the column layout, through one grid action group, so a key, its menu item and a host's button share one enabled state.
• Pure rules move to services::grid (column, display text, editability, edit parsing, policy, copy scope, layout, find, filter rules), tested without GTK.
• Rows live in stable slots (GridStore, GridRow with a generation), so a reload rewrites data in place instead of rebuilding every cell widget. Anything that acts later (menu, editor, copy, paste, delete question) holds a PinnedRow.
• A row number column carries each row's pending icon and accessible description; changed values are bold in Adwaita's warning colour and deleted rows struck through. The row tints, the error flash and its timer are gone: a failed save marks its row until it is edited or saved again.
• Row Details pane (AdwOverlaySplitView, Alt+Return) with every field of the focused row and an editor for long text, JSON, XML and dates; the popover editors are gone.
• Inline editing: F2, Return, a double click or typing on a cell (dead keys and Compose included); a refused value stays in the editor with its reason; Tab moves to the next editable cell. A click focuses the cell under it (GTK gives a column view cell no click of its own) and a right click the row it is on, so Row Details and the keys act on what was clicked.
• Columns open wide enough for their longest sampled value, measured with Pango. Drag to reorder, hide and show (header menu, cell menu, Columns dialog), sizes per column type; order, hidden columns and widths are kept per table in the column layout file, now version 2 (a version 1 file of widths upgrades on read). A save writes only what that grid changed, so two tabs on one table keep each other's changes.
• Find in SQL results and key tabs (Ctrl+F, Ctrl+G); Ctrl+F stays Filter in table tabs. Filter by Value and Exclude Value add a rule to the table tab's filter strip.
• Copy (Ctrl+C everywhere): the focused cell's value for one row, the rows otherwise; Copy As, export, Show Row as JSON and the INSERT copy take the columns on screen in their order.
• Fixed: Ctrl+C did nothing in SQL results and key tabs (D2); Insert Row and Duplicate in the menu of a keyless table saved rows with no key (D1); Ctrl+S skipped the value being typed (D5); a row marked for deletion took edits that were never saved (D8); MongoDB fields with . or a leading $ could be sorted and edited and then failed at the server (D4); the selection count offered Delete where it did nothing (D12); booleans drew three ways and made rows taller (D9, D10); tint gaps (D11) and the flash on a dragged column (D13) went with the tints.
• platform-linux.md (fix-issue): dark and light shots take ADW_DEBUG_COLOR_SCHEME=prefer-dark or prefer-light; libadwaita ignores force-dark.
• ADR 0027 records the grid; ARCHITECTURE.md, docs/storage.md, docs/testing.md and docs/regression-tests.md follow.
• Tests changed on purpose: rejected_edit_restores_cell_display (a refused value now stays in the editor), the popover editor tests (editors moved to the pane), the check button tests (booleans are text), menu_item_shows_local_and_component_keys (Copy now shows Ctrl+C), the tint and flash tests, page_rows_have_single_owner (the slot keeps a reference), the page-turn store change (slots are reused), kill_during_save (opens the editor with grid.edit; the per-cell double-click gesture is gone).

Test plan

• verify.sh --platform linux test tablepro in the CI image: 2411 passed, 0 failed, every integration binary included; mouse clicks and double clicks driven through XTEST.
• New: 102 core grid tests, the edit controller, copy and references, row detail pane, find, column chooser and layout store tests; host tests for the table tab, SQL results and key tab; F-004 and F-005 guards kept.
• clippy with and without default features, rustfmt, POTFILES.

Before	After

Needs the maintainer

• Retake linux/data/screenshots/01-table.png and 02-editor.png on a GNOME desktop (README, Screenshots): the window shadow and rounded corners take a compositing window manager with _GTK_FRAME_EXTENTS, which the CI image under Xvfb does not have.