Fix spawn placement under the top bar, add per-window minimum sizes, and clean up maximize

Four reports after restarting into today's build, with a screenshot. The
screenshot was measured, not eyeballed: top bar y=0..29, a 4px accent border
at y=30..33, titlebar from y=34, bottom border at y=1027..1030, and 49px of
bare desktop below it.

Windows spawning too close to the top bar. A remembered position was
validated only by asking whether it landed on some monitor's full_geometry,
which includes the strip a top bar reserves, so an app whose remembered y was
small reopened with its titlebar under the bar. That is why it was
"sometimes": it depended on the stored value, and the live store holds
wezterm at y=44 and firefox at y=69 against a 30px bar. Remembered positions
are now clamped into the monitor's usable area.

Placement not surviving a logout. Window memory does persist, but five of the
eleven entries in the live store were saved with a second monitor attached,
at x >= 2000. Those points match no current monitor and were discarded
outright, falling back to a fresh cascade, so those apps appeared to remember
nothing. Such a position is now clamped onto a monitor that exists instead.

Per-window minimum sizes. One global floor is wrong in both directions.
Three sources now, in increasing precedence: the global floor, the client's
own declared minimum (xdg_toplevel.set_min_size or ICCCM hints), and a
min_width/min_height window rule overriding both. A rule wins permanently --
the backend refreshes the client's declared minimum on every decoration
redraw and must not undo a deliberate override.

Maximize, three faults in one report. A maximized window now draws no
border: its edges are the screen's edges, and the only place maximize stops
short is the bar strip, which is exactly where the measured line was.
maximize_geometry_for no longer subtracts a bottom-anchored dock's exclusive
zone, so maximize runs to the bottom of the screen and the dock floats over
it; top, left and right are still honoured.
general.maximize_covers_dock = false restores the old behaviour. With the
border gone the window sits flush under the bar instead of with an accent
line crowding it.

Verified: seven new tests on the real numbers from the live store, and
maximize geometry measured live in a nested instance (a window maximized on a
split half reports exactly that half's rect). NOT confirmed on screen: the
border removal and the dock behaviour - the nested backend has no bar or
dock to reserve a zone, and an attempt to check the border produced a failing
control, since srd set border_width only affects windows created after it.

515 tests pass, clippy clean.

1 files changed, 6 insertions, 0 deletions

diff --git a/crates/core/src/manager/mod.rs b/crates/core/src/manager/mod.rs
index e778a32..2ca2bf9 100644
--- a/crates/core/src/manager/mod.rs
+++ b/crates/core/src/manager/mod.rs
@@ -434,6 +434,11 @@ pub struct WindowManager {
     /// Read from `theme.lock.*`. See `LockConfig`'s own doc comment for
     /// why this isn't just folded into `theme` above.
     pub lock: LockConfig,
+    /// `general.maximize_covers_dock`: whether maximize runs to the bottom
+    /// of the screen, under a bottom-anchored dock, rather than stopping
+    /// above it. A top bar's own reservation is always honoured either
+    /// way. Default `true` - see `input::layers::maximize_geometry_for`.
+    pub maximize_covers_dock: bool,
     /// Set by `request_refresh`, drained by the main loop. Same
     /// cross-boundary queued-request shape as `lock_requested`.
     refresh_requested: bool,
@@ -623,6 +628,7 @@ impl WindowManager {
             auto_raise: false,
             theme: ThemeConfig::default(),
             lock: LockConfig::default(),
+            maximize_covers_dock: true,
             refresh_requested: false,
             live_settings: std::collections::BTreeMap::new(),
             drag: None,