docs(audit): record final player-experience parity

Add the requirement-by-requirement audit for the Rust rewrite. It ties visual,
audio, input, physics, timer, rule, multiball, player, persistence, random, and
build claims to the preserved binary, complete readable C, focused tests,
deterministic framebuffers, and stopped-Wine differential probes.

The audit distinguishes native-window and portable-storage substitutions from
gameplay semantics, records both relative-slingshot position/velocity/spin
probes, and lists the reproducible final gates used for the completion decision.

Test Plan:
- `cargo build --profile production` -- passed
- `cargo test --workspace --all-targets --all-features` -- 125 passed
- `cargo clippy --workspace --all-targets --all-features -- -D warnings` -- passed
- Windows and macOS `cargo check` targets -- passed
- `bash original/tools/test_reconstructed_c.sh` -- passed
- `python3 original/tools/audit_reconstruction.py --require-complete` -- passed with zero incomplete or unclassified units
- original executable, timer DLL, and preserved raw hashes -- matched
- `rumdl check --flavor commonmark README.md RECONSTRUCTION.md PARITY_AUDIT.md CHANGELOG.md` -- passed
- `git diff --cached --check` -- passed

tdkpin-rs/PARITY_AUDIT.md

@@ -0,0 +1,83 @@
+# Rust player-experience parity audit
+
+Audit date: 2026-08-23
+
+## Decision
+
+The Rust rewrite passes the reconstructed-binary requirements for the same game
+and player experience at the 640x460 logical gameplay boundary. No known raw,
+placeholder, guessed, partial, or unverified gameplay unit remains in the Rust
+path. This is a semantic and presentation result, not a claim that a native
+Rust executable is a byte-identical Win16 implementation.
+
+The authoritative source is the preserved executable with SHA-256
+`a9022f1894e3e6e21fc42e8f6c932f7c549ca77f63aaa0c488bb9d55d9d0174c`,
+the complete readable C under `../original/reconstructed/`, and the zero-gap C
+ledger in `../original/C_RECONSTRUCTION_FINAL_AUDIT.md`.
+
+## Requirement matrix
+
+| Requirement | Binary/C basis | Rust evidence | Result |
+| --- | --- | --- | --- |
+| Original presentation | All 63 resources round-trip; DAT/bitmap bounds and GDI call sites are reconstructed | Original images/samples are embedded; loading, attract, game, panel, target, effect-seven, high-score, and name-entry scenarios export 640x460 frames | Verified |
+| Collision inventory | All 175 initialized records are typed in `OBJECTS.tsv`; raw scan order is address-linked | 109 type-2 lines, 40 type-1 circles, all type-3/4 mechanisms, layer masks, response fields, and initial activity are represented; relative chains 54-59 and 69-74 have record-exact tests | Verified |
+| Fixed-point/Real48 physics | `1000:c79c` and Borland runtime arithmetic are reconstructed; the DOS reference probe is bit-exact | 10 ms millipixel steps, both speed clamps, four board bounds, first-record selection, signed dot-product tangent response, spin, auxiliary kick, and dynamic-ball transfer use exact-width arithmetic | Verified |
+| Live collision behavior | Stopped Wine probes expose position, velocity, and six-byte spin | Rails, circles, bumper, record 2, record 57, and record 72 have exact expected transitions in Rust and C tests | Verified |
+| Timer ordering | `1000:eab1` fixes 5/4/3/2/1 substeps, ball-slot order, countdowns, mechanisms, flippers, and Tilt decay | Timer-batch, collision-break, per-slot, target-rotation, panel, claw, countdown, and Tilt tests cover the recovered callback order | Verified |
+| Attract mode | Raw `1000:01b7-063b` distinguishes quotient and remainder outputs; marquee GDI lifetime is reconstructed | `%32/2`, `%32/4`, `%40/4`, `%16/4`, `%144/8`, magnetic `%32`, and six-callback marquee cycles are tested and rendered | Verified |
+| Inputs | `1000:638e/6bf8` define low-byte scans, Key-Up actions, auxiliary-window gate, launcher impulses, nudges, Tilt, and flipper latches | Both Ctrl/Enter aliases, both plus positions, release-time add/nudge/F12, held launcher, flipper rearm, and auxiliary-window blocking follow those paths | Verified |
+| Rules and scoring | `1000:b476`, `1000:c4e1`, `1000:bc36`, `1000:ae6e`, and `1000:9e85` define awards and state transitions | Bank progression, ninth-diamond order, ball-scoped double, marker comparison, lock transfer, special hole, all seven effects, Type-3 Tilt finish, and score/sound ordering have focused tests | Verified |
+| Multiball | Records 148, 174, and 175 plus timer collapse/spawn paths define ownership and lifetime | Deferred spawn, per-slot capture age, survivor promotion, no-third-ball guard, nudge, fifth-lock deferral/reset, special respawn, and contact clearing are tested | Verified |
+| Player turns | `1000:ae6e` saves all record activity/contact mirrors and advances live players | Four-player bounds, add-before-launch, per-player rule state, final-ball high-score ordering, flipper key lifetime, and normal/special drain behavior are tested | Verified |
+| Audio | Sixteen WAV resources and every in-image play/stop call are inventoried | Samples are unchanged; monophonic async replacement, full volume, Tilt suppression, threshold precedence, panel stops, and no-WAV-2022 behavior are represented | Verified |
+| High scores/configuration | The 276-byte `IWIK` table, dialog 32514, HighScore child, and INI reads are reconstructed | Signed-high comparisons, all ten entries, 21-byte name semantics, OK/Cancel flow, localized help, original settings names/defaults, and screenshots are tested | Verified |
+| Randomness | The Borland LCG, high-product `Random(n)`, Real48 result, and program-global seed are reconstructed | All gameplay draws use one exact stream; seeded traces are repeatable and the final seed continues across games | Verified |
+| Stability/build | Native replacement must preserve finite state and compile on supported hosts | Production Linux build, 125 Rust tests, strict Clippy, two-minute finite autoplay, and Windows/macOS cross-target checks pass; native CI covers all three hosts | Verified |
+
+## Differential evidence
+
+- Record 2 special response:
+  `(157000,453000)/(0,3000)` publishes the special ball at
+  `(17000,23000)/(0,3040)` and continues to
+  `(16698,21191)/(-302,-1809)`.
+- Record 57 left relative slingshot:
+  `(75530,354765)/(3000,15)` becomes
+  `(77369,356597)/(1839,1832)`, Real48 spin `-5.28`
+  (`83 5d 8f c2 f5 a8`).
+- Record 72 right relative slingshot:
+  `(235348,356825)/(-3000,15)` becomes
+  `(233253,358494)/(-2095,1669)`, Real48 spin `+5.46`
+  (`83 86 eb 51 b8 2e`).
+- Ordinary circle 155, the outer/inner shooter rails, bumper response, all four
+  claw terminals, moving flippers, Type-3/4 records, scoring, and multiball
+  also have focused C/Rust or Wine-backed tests documented in
+  `RECONSTRUCTION.md`.
+
+## Deliberate host substitutions
+
+- The native fixed window replaces ObjectWindows/Win16 ownership, but retains
+  the title, logical client size, original pixels, controls, modal gameplay
+  blocking, and visible flows.
+- Portable JSON replaces writes to `HISCORES.DAT` and `TDKPIN.INI`; the original
+  files are imported, while table ordering, names, settings, and UI semantics
+  remain unchanged. F9/F10 expose additional viewers/settings without replacing
+  any original gameplay key.
+- Windows and macOS were cross-checked in this Linux checkout; native execution
+  on those hosts is delegated to the repository's three-OS CI matrix. The
+  semantic core is platform-independent and has no target-specific branches.
+
+## Reproducible final gates
+
+```sh
+cargo build --profile production
+cargo test --workspace --all-targets --all-features
+cargo clippy --workspace --all-targets --all-features -- -D warnings
+cargo check --target x86_64-pc-windows-gnu
+cargo check --target x86_64-apple-darwin
+bash original/tools/test_reconstructed_c.sh
+python3 original/tools/audit_reconstruction.py --require-complete
+```
+
+The C ledger gate reports zero raw, partial, restored, unknown, blocked, or
+unclassified required units. The only files intentionally outside commits are
+user diagnostic media in the repository root.