feat(gui): port the Preferences sidebar to wxDataViewCtrl (#180 phase 1) - #671

Mechanical rebase to resolve conflicts against master's amule-org#642/amule-org#643 --
no source changes here. Resolved a real conflict in amuleDlg.cpp's
event table: amule-org#642 added the Alt+<letter> EVT_MENU block right where
this branch removed the EVT_TOOL(ID_BUTTONCONNECT, ...) line; kept
amule-org#642's block, dropped the connect-button line as intended.

Regenerated again via scripts/update-po.sh after later rebasing onto
master's amule-org#671 (Preferences sidebar) and amule-org#665/amule-org#662 (amuleapi
credentials, sparse part-file setting), which had added strings this
branch's catalogs didn't have yet.

Mechanical rebase to resolve conflicts against master's amule-org#642/amule-org#643 --
no source changes here. Resolved a real conflict in amuleDlg.cpp's
event table: amule-org#642 added the Alt+<letter> EVT_MENU block right where
this branch removed the EVT_TOOL(ID_BUTTONCONNECT, ...) line; kept
amule-org#642's block, dropped the connect-button line as intended.

Regenerated again via scripts/update-po.sh after later rebasing onto
master's amule-org#671 (Preferences sidebar) and amule-org#665/amule-org#662 (amuleapi
credentials, sparse part-file setting), which had added strings this
branch's catalogs didn't have yet.

* feat(gui): remove the global Connect/Disconnect toolbar button

Closes #402. Per-network controls already exist (Kad pane's Start/Stop,
Servers pane's ED2K connect/disconnect), the connection state is
already shown in the status bar, and after discussing relocating it
into the Networks view the agreed call (got3nks + ngosang) was simply
to remove it -- mirrors what #585 already did on the Web UI side.

Removed the toolbar tool, its three skin icons (Toolbar_Connect/
Disconnect/Connecting) and their bitmap wiring, the button-update block
in ShowConnectionState(), and the two EnableTool(ID_BUTTONCONNECT, ...)
call sites.

CamuleDlg::OnBnConnect() itself stays -- CMuleTrayIcon::DoConnectDisconnect()
still calls it for the tray icon's own connect/disconnect action, which
is unaffected by this change.

ShowConnectionState()'s skinChanged parameter was only ever read by the
now-removed block, so it's gone too, along with the one call site that
passed true and the forceUpdate plumbing that reached it through
GuiEvents.cpp's ShowConnState() free function.

Left ID_BUTTONCONNECT and muuli_wdr.cpp's muleToolbar() (which still
calls it) alone -- that function predates Apply_Toolbar_Skin, is never
called anywhere, and touching pre-existing dead code is out of scope
for this fix.

Verified: built and ran both amule and amulegui cleanly, full unit
test suite passing (26/26). Confirmed via the po/ diff that "Connect"/
"Disconnect"/"Cancel" remain in the catalog (still used by other
per-network buttons) -- only their now-orphaned toolbar-specific
tooltip strings were dropped. Could not get a real on-screen visual
confirmation of the toolbar layout -- same macOS Accessibility
automation limitations as #180 got in the way of screenshotting the
actual app window.

* i18n: regenerate po/ catalogs after rebasing onto current master

Mechanical rebase to resolve conflicts against master's #642/#643 --
no source changes here. Resolved a real conflict in amuleDlg.cpp's
event table: #642 added the Alt+<letter> EVT_MENU block right where
this branch removed the EVT_TOOL(ID_BUTTONCONNECT, ...) line; kept
#642's block, dropped the connect-button line as intended.

Regenerated again via scripts/update-po.sh after later rebasing onto
master's #671 (Preferences sidebar) and #665/#662 (amuleapi
credentials, sparse part-file setting), which had added strings this
branch's catalogs didn't have yet.

* feat(gui): turn the per-network Disconnect buttons into Connect/Cancel/Disconnect toggles

Relocates the removed global toolbar button's functionality into the
ED2K (IDC_ED2KDISCONNECT) and Kad (ID_KADDISCONNECT) panes instead of
just dropping it, per got3nks's proposal on #663: each button now
mirrors ed2kState/kadState (off/connecting/connected) using the
existing connButImg() bitmaps, and can independently connect or
cancel/disconnect its own network -- something the old OR-toggled
global button never allowed. The ED2K pane also gains a Connect
button it never had (previously Disconnect-only).

CServerWnd::UpdateED2KConnectButton() / CKadDlg::UpdateConnectButton()
are called from CamuleDlg::ShowConnectionState() alongside the
existing UpdateED2KInfo()/UpdateKadInfo() calls, and once from each
pane's own ctor/Init() for the initial paint. OnBnClickedED2KDisconnect
and OnBnClickedDisconnectKad gained the missing "connect when off"
branch; OnBnConnect and the tray icon are untouched.

Verified interactively on Windows: both buttons show the correct
label/icon for their live state, ED2K disconnect/reconnect works from
its own button, and disabling ED2K in Preferences while Kad stays
connected confirms the two toggle independently.

po/ regenerated via scripts/update-po.sh to match the new button
labels ("Disconnect Kad" is now unused and moves to the obsolete
section; no new translatable strings).

* fix(gui): drop the per-network connect-button state cache

got3nks flagged two bugs in review (PR #663): the static cache's
early return also skipped Enable(), so the button could get stuck
disabled once IsReady()/network-pref state changed without the
Connect/Cancel/Disconnect state itself changing (master had two now-
deleted escape hatches -- the skinChanged force-path and an
unconditional EnableTool call -- that used to paper over this). Worse,
the cache was function-scope static, surviving widget recreation, so
a fresh pane's Init() call could early-return and leave the wxDesigner
default label ("Disconnect Kad") on screen.

Dropping the cache removes both: SetLabel/SetBitmap/Enable are cheap
on a plain wxButton (unlike the old toolbar tool, which had real
native-image-list reasons to memoize, see amuleDlg.cpp:1054-ish), and
master's own second call site already did an unconditional EnableTool
every tick without issue.

Second review round (macOS + Ubuntu ARM64, monolithic + amuleGUI)
confirmed the toggle works functionally but flagged three cosmetic
issues, all fixed here:

- No gap between the connect-button icon and its label. The obvious
  fix, wxButton::SetBitmapMargins(), is NOT portable (wxOSX overrides
  it, wxGTK inherits the base no-op) -- prefixing the label with a
  literal space outside the _() call behaves identically on both and
  introduces no new msgid.
- The Kad button was stretched full-width by its sizer's .Expand()
  flag, while the ED2K one sizes naturally; GTK and macOS then filled
  the slack differently (centered vs. icon-left). Dropped .Expand()
  so the two buttons size the same way -- trades away lining up with
  the "Bootstrap from known clients" button above it, but the two
  connect buttons reading as the same control matters more.
- CServerWnd::UpdateED2KConnectButton() and CKadDlg::UpdateConnectButton()
  were near-identical (same 3-state enum, same switch, same three
  bitmaps). Factored into a shared SetConnectButtonState(button, state,
  enabled) helper in muuli_wdr.cpp/.h, next to connButImg() which it
  reuses -- so the icon-spacing fix above lives in one place instead
  of two.

Verified interactively on Windows: re-tested full disconnect/reconnect
cycle on both panes, toggling ED2K off and back on via Preferences
(existing behavior: needs an app restart to re-enable) with correct
state on the fresh post-restart paint, and confirmed by screenshot
that both buttons now show a visible icon/label gap and size the same
way (Kad no longer stretched). Also confirmed amulegui (CLIENT_GUI)
builds clean with these changes; did not perform full interactive
remote-daemon testing.

* fix(gui): first-paint layout bug + connect-button placement, per review

Two more issues from got3nks's Linux/GTK pass on #663.

1. Bug: the ED2K connect button painted with the icon overlapping the
   label on first show (Kad was fine, only by luck of timing).
   CServerWnd::UpdateED2KConnectButton() runs after sizer->Show(this,
   TRUE) in the ctor, so SetBitmap() grows the button's best size
   after the row was already measured against the text-only label,
   and nothing re-lays it out until a window resize. Fixed by calling
   Layout() on the button's parent at the end of the shared
   SetConnectButtonState() helper -- covers both panes, and stops Kad
   from relying on being laid out late (its notebook page is only
   measured once shown, after Init() already set its bitmap).

2. Layout: moved both connect/disconnect toggles to lead their pane
   instead of sitting among secondary controls, per got3nks's request:
   - ED2K (serverListDlgUp): toggle now on its own top row, right-
     aligned via a stretch spacer, directly above the server list.
     The "Add server manually" form (name/IP/port/Add) moved below
     the table instead of sharing a row with the toggle; the vertical
     separator that used to sit between them is gone (no longer
     needed once they're not adjacent).
   - Kad (KadDlg): toggle moved out of the "Bootstrap" static box
     (where it sat under "Bootstrap from known clients") to its own
     top row above the box, right-aligned the same way as ED2K's.
     item0 changed from a 1x1 FlexGridSizer (which only ever held the
     two-column area) to a plain vertical wxBoxSizer so it can hold
     the new top row plus the existing two-column layout.

Both panes now read "primary control on top, secondary/manual
controls below" -- matching shape on both tabs.

Verified interactively on Windows: screenshotted both panes, confirmed
no icon/label overlap on first paint (no window resize needed), and
re-ran the disconnect/reconnect toggle cycle on both after the layout
change.