v0.4.0 final review: D404 pad-centred aim (N64-parity quadratic curve) + full campaign-playtest sign-off bookkeeping

- input.c: padDirectCompute() — pad twin of the mouse Centred aim; the natural
  pitch path routes AIMMODE_CENTRED through it, AIMMODE_N64 keeps classic
  stick-deflection behavior. Parity pass uses bondview2's verbatim N64
  quadratic curve (sign(v)*clamp(defl/70,+-1)^2 * fov/60 * 3.5 deg/poll), so
  full-stick Centred matches N64's top rate exactly.
- optionsoverlay: aim rows device-neutral (Aim style / Aim range).
- findings.md: D404 RESOLVED (user-validated on Steam Deck, both passes);
  21 sign-off status updates from the user's full campaign playtest
  (D175/D224/D235/D236/D240/D241/D245/D249/D281/D286/D287/D289/D291/D294/
  D303/D306/D307/D308/D311/D320/D322/D75/D387/D395/D396/D399/D400); stale
  options-wave rows closed (D346-D391 batch); D383/D394 kept PARTIAL with
  v0.5.0 scopes; D281 root cause -> v0.5.0; D258 -> NTSC-only for v0.4.0.
- README: Known issues = the true residual set (D318, D75 Rareware logo,
  AllUnlocked EXPERIMENTAL, NTSC-only); stale v0.3.0 clause removed.
- AGENTS.md: native-reexec guard status re-confirmed for 2026-09-28.

port/src/input.c

@@ -496,6 +496,7 @@ static int aimGepdAccumulate(double dxPx, double dyLook);
 static void aimGepdEdgeScroll(void);
 static int aimGepdCompute(double dxPx, double dyLook);
 static int hipDirectCompute(double dxPx, double dyLook);
+static int padDirectCompute(int dx, int dy);   /* D404: pad twin of the above */
 /* D194: bondview2's "look-ahead" pitch centreing (docentreupdown) arms during
  * hip-fire walking whenever the pitch strays from the horizon target, and --
  * once armed -- keeps pulling vv_verta back to it even in aim mode, EXCEPT
@@ -1973,8 +1974,22 @@ unsigned inputComputePad(int idx, signed char *stick_x, signed char *stick_y)
                 rys = (int)lround(padSmSY[idx]);
             }
             if (padLookInvertY) rys = -rys;
-            if (rxs) sx = rxs;
-            if (rys) sy = rys;
+            if (aimModeGet() == AIMMODE_CENTRED && padDirectCompute(rxs, rys)) {
+                /* D404 (resolved by implementation, 2026-09-28): pad CENTRED
+                 * aim -- the stick drives the camera directly (crosshair
+                 * pinned at centre), the pad-side twin of the mouse CENTRED
+                 * branch above, so the Aim-style toggle is no longer inert
+                 * on a pad. No look stick is emitted this poll; when
+                 * padDirectCompute declines (dead/watch/pause/cutscene) the
+                 * legacy stick emission below runs, as the mouse branch
+                 * falls back to its legacy path. AIMMODE_N64 keeps today's
+                 * behaviour: the deflection feeds the game's crosshair
+                 * integrator (travel + edge scroll + spring-back -- the
+                 * original controller feel). */
+            } else {
+                if (rxs) sx = rxs;
+                if (rys) sy = rys;
+            }
         } else {
             int px = scaleAxis(lx, padDeadzoneL);
             int py = -scaleAxis(ly, padDeadzoneL);       /* SDL up = negative -> N64 up = positive */
@@ -2550,6 +2565,64 @@ static int hipDirectCompute(double dxPx, double dyLook)
     return 1;
 }
 
+/* D404 (resolved by implementation, 2026-09-28): the pad-side twin of
+ * hipDirectCompute's CENTRED path -- the right stick drives the camera
+ * directly and the crosshair stays pinned at centre, so the Aim-style
+ * toggle is no longer inert on a pad (it used to be: the pad always
+ * emitted deflection into the game's N64 crosshair integrator, i.e. it
+ * was *always in N64 mode*). Same safety gates as hipDirectCompute
+ * (dead / watch / pause / scripted camera); the mouseDirectLook/
+ * mouseGrabbed gate is dropped -- it is meaningless for a pad. Input
+ * units are stick deflection (STICK_MAX = full, the same unit the N64
+ * path feeds the game's integrator).
+ *
+ * Gain = the N64 natural-turn curve VERBATIM (bondview2.c, canNaturalTurn
+ * / canNaturalPitch branches): v = clamp(deflection/70, \u00b11); v =
+ * sign(v)\u00b7v\u00b2; camera += v \u00b7 (fov/60) \u00b7 3.5 deg/poll. First pass used a
+ * linear 2.0 deg/poll \u00b7 (fov/GEPD_BASE_FOV) gain, which the user measured
+ * as a dramatic sensitivity loss in Centred mode (linear vs quadratic
+ * curve, and the 60-vs-90 FOV base compounded it to ~2.6\u00d7 slower at full
+ * stick). With the verbatim curve, full-stick Centred turns at exactly
+ * the N64 path's top rate -- switching modes changes the crosshair
+ * behaviour, not the feel. */
+static int padDirectCompute(int dx, int dy)
+{
+    struct player *p = g_CurrentPlayer;
+
+    if (p == NULL)
+        return 0;
+    if (p->bonddead || !p->outside_watch_menu || p->pause_state != 0)
+        return 0;
+    if (gameScriptedCameraActive())
+        return 0;
+
+    if (dx == 0 && dy == 0)
+        return 1;   /* nothing to turn; caller simply emits no stick */
+
+    f32 fov = viGetFovY();
+    double k = (fov > 0.0f) ? (double)fov / 60.0 : 1.0;   /* bondview2's base */
+    double v;
+
+    v = (double)dx / 70.0;   /* analogTurn = raw stick \u00b1 5, /70 -- bondview2.c:6222 */
+    if (v > 1.0) v = 1.0; else if (v < -1.0) v = -1.0;
+    if (v >= 0.0) v *= v; else v = -v * v;
+    p->vv_theta += (f32) (v * k * 3.5);
+
+    v = (double)dy / 70.0;   /* analogPitch, /70 -- bondview2.c:6161 */
+    if (v > 1.0) v = 1.0; else if (v < -1.0) v = -1.0;
+    if (v >= 0.0) v *= v; else v = -v * v;
+    p->vv_verta -= (f32) (v * k * 3.5);   /* game: speedverta = -v\u00b7(fov/60) */
+    if (p->vv_verta >  90.0f) p->vv_verta =  90.0f;
+    if (p->vv_verta < -90.0f) p->vv_verta = -90.0f;
+
+    if (configGetInputLog()) {
+        sysLogPrintf(LOG_NOTE,
+            "GE_INPUTLOG paddirect d=(%d,%d) cam=(%.1f,%.1f)",
+            dx, dy, (double)p->vv_theta, (double)p->vv_verta);
+    }
+    return 1;
+}
+
 /* --- Input.PdMouseAim: the port side of PD's mouse-aim model ----------------
  * See the flag's comment above for the design. PD's own implementation lives
  * in its GAME files (bondmove.c/bondgun.c) behind `#ifndef PLATFORM_N64`, with

port/src/optionsoverlay.c

@@ -207,8 +207,15 @@ static struct Row rows[] = {
      * overrides it at launch for A/B runs. */
     /* D337: N64 = the N64 aim model (crosshair travels, camera edge-scrolls)
      * with the mouse fed through the game's integrator at PD's mouse damp --
-     * the default. CENTRED (PC) = opt-in FPS-style aim (#104), not N64. Applies
-     * to every aim input (RMB, Shift, Q/L, pad trigger, Toggle mode). */
+     * the default. CENTRED (PC) = opt-in FPS-style aim (#104), not N64.
+     * Device-neutral (D404, resolved by implementation 2026-09-28): mouse --
+     * N64 feeds the game's integrator, CENTRED drives the camera directly
+     * (hipDirectCompute); pad -- N64 emits right-stick deflection into the
+     * same integrator (the original controller feel: crosshair travel +
+     * edge scroll + spring-back), CENTRED drives the camera directly from
+     * the stick (padDirectCompute, crosshair pinned at centre). Applies to
+     * every aim input (RMB, Shift, Q/L, Toggle mode, pad right stick in
+     * natural-pitch mode). */
     { .key="Input.AimMode", .label="Aim style", .kind=ROW_ENUM, .step=1, .names=kAimMode },
     /* D338: how far the N64-style crosshair travels. PC = to the screen edge
      * (GEPD / mouse-injector feel, default); N64 = the original stick limits
@@ -222,9 +229,9 @@ static struct Row rows[] = {
      * (natural-pitch) feel options, identity at their defaults. All port-layer. */
     { .key="Input.PadDeadzoneL", .label="Deadzone (left stick)", .kind=ROW_SLIDER, .step=500 },
     { .key="Input.PadDeadzoneR", .label="Deadzone (right stick)", .kind=ROW_SLIDER, .step=500 },
-    { .key="Input.PadLookSensX", .label="X axis look sensitivity", .kind=ROW_SLIDER, .step=5 },
-    { .key="Input.PadLookSensY", .label="Y axis look sensitivity", .kind=ROW_SLIDER, .step=5 },
-    { .key="Input.PadLookSmooth", .label="Look smoothing", .kind=ROW_SLIDER, .step=1, .dispMax=10 },
+    { .key="Input.PadLookSensX", .label="X axis look sensitivity (controller)", .kind=ROW_SLIDER, .step=5 },
+    { .key="Input.PadLookSensY", .label="Y axis look sensitivity (controller)", .kind=ROW_SLIDER, .step=5 },
+    { .key="Input.PadLookSmooth", .label="Look smoothing (controller)", .kind=ROW_SLIDER, .step=1, .dispMax=10 },
     { .key="Input.PadSouthpaw", .label="Southpaw", .kind=ROW_TOGGLE, .step=1, .names=kOnOff },
     { .key="Input.PadTriggerPct", .label="Trigger threshold", .kind=ROW_SLIDER, .step=1 },
     /* D401 item 3 (docs/dev/RUMBLE-PLAN.md): Rumble Pak strength (D224