Add a PC renderer for the themed pages; fix overlapping layouts

tools/render_pages.py compiles the page code natively with g++ against
ESPHome's own display and font code and the font bitmaps of the last
`esphome compile`, and draws pages to PNG at chosen moments with sample
data (normal, empty, alert, busy), as a contact sheet, or as one example
per page in docs/images/pages (now shown in the README).

Fixes found with it: Cyber HUD zone names ran into the temperatures,
the breach header label hit the tag and the column marker the matrix
label; KonoSuba subtitle, guild weather icon, cabbage text and all-day
deadline, and hills through the party; Steins;Gate D-mail recipient, the
microwave display, the gadget card value and world line labels; LCARS
room rows, readout bars and data cascade, warp core readouts, and the
captain's log weather wording.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/render/el512_display.h

@@ -0,0 +1,104 @@
+// Host stand-in for components/el512/el512_display.h, used by
+// tools/render_pages.py to draw the themed pages on a PC: the same drawing
+// surface (ESPHome's Display, 512 x 256, 1 bpp) and the same buffer effects,
+// without the panel, DMA or ESPHome components.
+#pragma once
+
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+
+#include "cyberpunk.h"
+#include "el512_helpers.h"
+#include "esphome/components/display/display.h"
+#include "esphome/core/hal.h"
+#include "konosuba.h"
+#include "steins.h"
+#include "trek.h"
+
+namespace esphome::el512 {
+
+class EL512Display : public display::Display {
+ public:
+  static constexpr int WIDTH = 512, HEIGHT = 256, ROW = WIDTH / 8;
+
+  uint8_t fb[ROW * HEIGHT]{};  // row-major, MSB = leftmost pixel (also PBM P4 order)
+  uint32_t shown_at{0};        // millis() when the page was "shown"
+
+  void update() override {}
+  display::DisplayType get_display_type() override { return display::DisplayType::DISPLAY_TYPE_BINARY; }
+
+  void fill(Color color) override {
+    if (this->get_clipping().is_set()) {
+      Display::fill(color);
+      return;
+    }
+    memset(this->fb, color.is_on() ? 0xFF : 0x00, sizeof(this->fb));
+  }
+  void draw_pixel_at(int x, int y, Color color) override {
+    if (!this->get_clipping().inside(x, y))
+      return;
+    this->set(x, y, color.is_on());
+  }
+
+  uint32_t page_age_ms() { return millis() - this->shown_at; }
+  uint32_t page_shown_at() const { return this->shown_at; }
+
+  // Same effects as the device (el512_display.cpp).
+  void shift_rows(int y, int height, int dx) {
+    dx %= WIDTH;
+    if (dx < 0)
+      dx += WIDTH;
+    if (dx == 0)
+      return;
+    uint8_t src[ROW];
+    for (int r = std::max(y, 0); r < std::min(y + height, HEIGHT); r++) {
+      uint8_t *row = this->fb + r * ROW;
+      memcpy(src, row, ROW);
+      memset(row, 0, ROW);
+      for (int x = 0; x < WIDTH; x++) {
+        const int s = (x - dx + WIDTH) % WIDTH;
+        if (src[s >> 3] & (0x80 >> (s & 7)))
+          row[x >> 3] |= 0x80 >> (x & 7);
+      }
+    }
+  }
+  void invert_rect(int x, int y, int width, int height) {
+    for (int py = y; py < y + height; py++)
+      for (int px = x; px < x + width; px++)
+        if (px >= 0 && py >= 0 && px < WIDTH && py < HEIGHT)
+          this->set(px, py, !this->get(px, py));
+  }
+  void dither_mask(int level) {
+    if (level >= 16)
+      return;
+    static const uint8_t BAYER[4][4] = {{0, 8, 2, 10}, {12, 4, 14, 6}, {3, 11, 1, 9}, {15, 7, 13, 5}};
+    uint8_t masks[4];
+    for (int r = 0; r < 4; r++) {
+      masks[r] = 0;
+      for (int x = 0; x < 8; x++)
+        if (BAYER[r][x & 3] < level)
+          masks[r] |= 0x80 >> x;
+    }
+    for (int y = 0; y < HEIGHT; y++)
+      for (int i = 0; i < ROW; i++)
+        this->fb[y * ROW + i] &= masks[y & 3];
+  }
+
+  bool get(int x, int y) const { return this->fb[y * ROW + (x >> 3)] & (0x80 >> (x & 7)); }
+  void set(int x, int y, bool on) {
+    if (x < 0 || y < 0 || x >= WIDTH || y >= HEIGHT)
+      return;
+    uint8_t &b = this->fb[y * ROW + (x >> 3)];
+    if (on)
+      b |= 0x80 >> (x & 7);
+    else
+      b &= ~(0x80 >> (x & 7));
+  }
+
+ protected:
+  int get_width_internal() override { return WIDTH; }
+  int get_height_internal() override { return HEIGHT; }
+};
+
+}  // namespace esphome::el512