feature: add mkdocs-material documentation site with CI deployment

Generate comprehensive documentation for all 173 source units and
integrate mkdocs-material into the build toolchain. Documentation
covers kernel core, x86 architecture, drivers, applications, and
all subsystems with a tabbed navigation structure.

- Add mkdocs.yml with material theme, mermaid support, and tabbed nav
- Add doc/index.md landing page
- Generate doc/src/ markdown for every Pascal unit in src/
- Reorganize planning docs into doc/planning/
- Add compat, lvglh, and toolchain doc sections
- Update Dockerfile to install python3 and mkdocs-material (pinned <2)
- Replace pasdoc-based compile_docs.sh with mkdocs build --strict
- Add compile_docs.sh to the main build pipeline in compile.sh
- Add deploy-docs step in .drone.yml with host volume mount to nginx
- Add site/.gitkeep for build output directory

doc/src/boot/boot.splash.md

@@ -0,0 +1,93 @@
+# boot.splash
+
+Boot splash screen displaying the Asuro logo, a progress bar, and a status label during kernel initialization.
+
+## Overview
+
+`boot.splash` renders a full-screen LVGL splash screen that is visible while `kmain` works through the boot sequence. Because the graphics render daemon (`svc.gfxd`) has not yet started at this stage, `boot.splash` drives the LVGL timer pipeline and flushes the framebuffer manually on every update.
+
+The screen uses a dark background (`#1A1A2E`) with a vertically-centred flex column containing three children: an LVGL image widget displaying the Asuro logo, a progress bar, and a status text label.
+
+The logo is decoded at runtime from a TGA file that is embedded in the kernel binary via a NASM `incbin` stub. The decoded ARGB8888 pixel buffer is wrapped in a heap-allocated `TLVImageDsc` that conforms to the LVGL `lv_image_dsc_t` layout so it can be passed directly to `lv_image_set_src`.
+
+`teardown` restores the previously-active LVGL screen, deletes all splash widgets, and frees the decoded texture and image descriptor.
+
+## Dependencies
+
+- `driver.video.lvgl`
+- `driver.video`
+- `core.fmt.targa`
+- `core.gfx.texture`
+- `memory.heap`
+
+## Constants
+
+### LV_IMAGE_HEADER_MAGIC
+`$19` — Magic byte placed in the first byte of the LVGL `lv_image_header_t`.
+
+### LV_CF_ARGB8888
+`$10` — LVGL color format constant for 32-bit ARGB8888 pixel data.
+
+### BAR_WIDTH / BAR_HEIGHT
+`300` / `16` — Progress bar dimensions in pixels.
+
+## Types
+
+### TLVImageHeader
+
+```pascal
+TLVImageHeader = packed record
+    magic_cf_flags : uint32;  { magic:8 | cf:8 | flags:16 }
+    w_h            : uint32;  { w:16 | h:16 }
+    stride_res     : uint32;  { stride:16 | reserved:16 }
+end;
+```
+
+Mirrors `lv_image_header_t` with manual bitfield packing. `magic_cf_flags` encodes `LV_IMAGE_HEADER_MAGIC` in bits 0–7 and `LV_CF_ARGB8888` in bits 8–15. `stride` is set to `width * 4` bytes per pixel.
+
+### TLVImageDsc / PLVImageDsc
+
+```pascal
+TLVImageDsc = packed record
+    header    : TLVImageHeader;
+    data_size : uint32;
+    data      : pointer;
+    reserved  : pointer;
+end;
+```
+
+Mirrors the 24-byte `lv_image_dsc_t` on 32-bit. `data` points to the decoded ARGB pixel buffer; `data_size` is `width * height * 4`.
+
+## Functions and Procedures
+
+### init
+
+```pascal
+procedure init;
+```
+
+Saves the currently active LVGL screen, decodes the embedded TGA logo, creates the splash screen with a flex-column layout, and renders the first frame. The image is scaled to 50% (`lv_image_set_scale(logoImage, 128)`).
+
+### update
+
+```pascal
+procedure update(percent: uint32; status: pchar);
+```
+
+Sets the progress bar value (clamped to 0..100), updates the status label text, redraws the frame, and calls `busywait_500ms` to hold the display visible for approximately 500 ms. Called by `kmain` at each boot milestone.
+
+### teardown
+
+```pascal
+procedure teardown;
+```
+
+Restores the previous LVGL screen, deletes the splash screen object and all its children, and frees the heap-allocated image descriptor and decoded texture.
+
+## Notes
+
+`busywait_500ms` reads the PIT channel-0 counter in a tight loop without using interrupts, making it safe to call before `STI`. It counts approximately 4000 PIT rollovers (~500 ms at a ~8 kHz tick rate). This is a debug-only mechanism intended to make each boot step visible on screen.
+
+The `redraw` helper passes a 100 ms tick increment to `lv_tick_inc` so LVGL always considers the display stale and renders pending invalidations immediately, without relying on the scheduler-driven tick source.
+
+The embedded TGA data is referenced via linker-provided symbols `_splash_tga_start` and `_splash_tga_size` inserted by the NASM `incbin` stub.