The vtable methods all have native Rust implementations now, so the
verbose docstrings that re-narrated each function's algorithm are
redundant — the Rust code itself is the source of truth.

Removes:
- The obsolete "GetSpriteFrameForBlit is NOT ported" pointer to a
porting blueprint that's been irrelevant since slot 33 landed.
- The full three-phase blueprint on the slot 11 vtable struct
docstring (duplicated in `draw_tiled_bitmap_impl` below).
- Most "Step N: do X" inline narration that just describes the next
line of Rust below it.
- Boilerplate `# Safety` sections that only said "must be a valid
pointer" — `unsafe fn` already implies that contract.
- Long algorithm walkthroughs on the simple ports
(`fill_rect`, `set_clip_rect`, `flush_render`, etc.).
- The 25-line panic explanation on the SpriteBank stub.

Kept (these add information the Rust code can't express):
- Original WA function name + Ghidra address on every port.
- Calling-convention quirks (usercall input registers, RET sizes).
- Intentional deviations from the original (the
`draw_tiled_bitmap_impl` pre-reservation, the `cbitmap_blit_via_wrapper`
EAX-return-value note, etc.).
- Cross-references to lessons / feedback files.
- Non-obvious behaviors that the Rust signature doesn't capture
(font_draw_text's "writes out_width even on validation failure",
load_font's leak-on-failure).

vtable.rs: 3448 → 2893 lines (-16%, -555 lines), no behavior changes.
Headless replay tests pass.