v0.5.0 playtest fold-in: fog and near-plane clip, crash fixes, polish (D540-D564)

Deck/Windows playtest fixes: fog rework (D540) and RSP-style CPU near-plane
clip with per-vertex N64 fog (D543), with fog recomputed on near-plane-clipped vertices as the RSP does,
so the haze around the player stays steady (D553); colour-combiner clamp for banded walls
(D548); rocket and thrown-item stack overflows (D545, D549); menu
double-trigger mitigation (D541); Dam ending first-shot camera swivel
restored by removing an old port look-at workaround (D552); settings standardisation (D546), live
All unlocked (D547), F10 mouse (D544); static window title and the project
mark (the in-game crosshair shape, site gold) as window/taskbar icon and
favicon (D550). Reference frames re-based
on Windows, Linux and Steam Deck (A/B-confirmed); capture_p7.sh runs on
Windows. Opt-in update check, off by default (D551: one HTTPS request to
GitHub per launch when enabled; winhttp.dll loaded only then; the tag CI
job checks the tag against GE007_VERSION). Release notes, ROADMAP,
internals and security docs updated; tree-hygiene pass.

Refs: D540 D541 D543 D544 D545 D546 D547 D548 D549 D550 D551 D552 D553 D554 D555 D556 D557 D558 D559 D560 D561 D562 D563 D564

docs/_layouts/default.html

@@ -11,7 +11,10 @@
        large image preview in search cards, which is what makes the
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   <meta name="robots" content="max-image-preview:large">
-  <link rel="icon" type="image/jpeg" href="{{ '/img/shots/shot-28.jpg' | relative_url }}">
+  <!-- Favicon: the project's own crosshair mark (tools_pc/make_icon.py),
+       not a game still -- original art, no derivative-work exposure. -->
+  <link rel="icon" type="image/png" href="{{ '/img/icon/ge007-icon.png' | relative_url }}">
+  <link rel="apple-touch-icon" sizes="512x512" href="{{ '/img/icon/ge007-icon.png' | relative_url }}">
   <!-- Entity disambiguation: the maintainer behind every page. -->
   <link rel="me" href="https://github.com/jkdansereau">
   {%- seo -%}