fix(gui): render the log views with wxStyledTextCtrl (Scintilla) - #548

The amuleGUI log panes used a wxTE_RICH2 (RichEdit) control, which holds the entire document and reflows O(n) on scroll. A remote-GUI first sync can deliver tens of thousands of daemon-log lines at once, so scrolling the "aMule Log" tab crawled, and the view mispainted — only the tail was visible until a manual one-line scroll (#547, follow-up to the #445 / #451 / #471 / #477 RichEdit repaint saga).

What changed

• New CMuleLogCtrl backed by wxStyledTextCtrl (Scintilla) replaces the three log/info panes: aMule Log, aMuleGUI Log, and server info. Scintilla renders only the visible lines, so scrolling and full-history retention stay O(visible) at any size, and — unlike a virtual list — it keeps character-level selection and find. Lines word-wrap as the old pane did; critical lines are bold via per-line Scintilla styles.
• The view tail-scrolls after new content only when it was already at the bottom, so scrolling up to read history isn't disturbed. When lines arrive while a pane is hidden — its notebook page or sub-tab isn't selected (e.g. the first-sync backlog before the Networks tab is opened, or the aMuleGUI Log / server info sub-tabs before you switch to them) — the control has no laid-out geometry and can't be scrolled reliably, so the tail-scroll is deferred and applied on the first idle once the pane is on screen. This lives in the base CMuleLogCtrl, so all three panes share it.
• This removes the whole RichEdit workaround stack — the per-poll append batching and the Freeze/Thaw lineage from perf(remote-gui): batch remote log delivery + rendering #451/fix(remote-gui): don't blank the log view on each new line (Windows) (#445) #471/fix(remote-gui): Windows repaint fixes — log-view blanking (#445) + list rows blanking on scroll/keyboard (#478) #477 — none of which Scintilla needs.
• wxStyledTextCtrl (the stc component) ships with the wxWidgets packages every platform already builds against (verified: Ubuntu libwxgtk3.2-dev, Homebrew wxwidgets, MSYS2 wxwidgets3.2, and the AppImage/flatpak source builds have wxUSE_STC on by default). No new dependency; stc is requested only for the GUI library that owns the log views, and the Windows packaging bundles its DLL automatically via the existing GET_RUNTIME_DEPENDENCIES install step.

Test plan

Verified on all three GUI platforms against a live remote daemon with a large multi-day log (~16k lines):

macOS (Cocoa, wx 3.3)

• First-sync backlog loads fast; scrolling the full history is instant (was crawling before).
• Backlog arriving while on the Networks tab → lands exactly at the bottom, then follows live lines.
• Backlog arriving while on another tab, then switching to Networks → lands exactly at the bottom (deferred-scroll path).
• aMuleGUI Log and server-info panes also land at the bottom when first opened (deferral is in the base control).
• Scroll up to read history → stays put as new lines arrive; switching tabs and back does not yank to the bottom.
• Critical (error/warning) lines render bold; normal lines normal.
• Text selection / copy works.

Linux (GTK3, wx 3.2)

• Same scenarios as above; scroll-to-bottom correct in both visible and hidden-during-load cases.

Windows (wxMSW, wx 3.2)

• Same scenarios; hidden-during-load deferred scroll lands at the bottom (matches macOS/GTK).
• Portable bundles wxmsw32u_stc_*.dll and launches cleanly.

Lint: clang-format clean; clang-tidy Tier-1 and Tier-2 diff checks both clean.