feat(core): adopt retail's SoundType catalog; retire AC2D

SoundId was not a subset of retail's table, the way its comment claimed.
It was an invention: 23 acdream-local names on acdream-local values, and
the values were wrong in the way that matters. FootstepDefault = 0x02 is
retail's Random. SwingSword = 0x10 is retail's Death2. Death = 0x60 is
retail's Explode. Anyone who reached for one of those names to compare
against a wire or dat value would have got a different sound.

Nothing referenced any of them by name -- grep for `SoundId.` across src
and tests returns nothing -- so this was a trap rather than a live defect,
the same shape the enum campaign found in DamageType. All 22 invented names
are deleted and retail's 205 replace them.

Three oracles agree exactly, on every name and every value: retail
acclient.h:4569 enum SoundType, ACE's Sound, and DatReaderWriter's Sound.
The third matters most. AudioHookSink already resolves SoundTable lookups
through DatReaderWriter.Enums.Sound, so that is the enum acdream actually
reads at runtime; our catalog now agrees with the values already flowing
through the dat path, and a conformance test pins the two so they cannot
drift apart.

On the "206 sounds" figure: retail's block holds 207 entries, being 205
sounds followed by NUM_SOUND_TYPES = 0xCD and FORCE_SoundType_32_BIT. The
first is a count and the second a width pin. Counting the former is where
206 came from. Neither is a member here, matching how the campaign treated
NUM_ATTACK_HEIGHTS and Num_HoldKeys -- a count is not a value the wire can
carry.

Behaviour is unchanged and could not be otherwise: the enum had no
consumers. IAudioEngine's three SoundId overloads are no-op stubs and the
live path takes wave ids and DatReaderWriter values.

The user's separate report that sound is "not working that good" is a
triggering, selection and attenuation question rather than a catalog one,
and is filed as its own Bucket B row in the post-Vulkan intake.

Also in this commit, by user decision: AC2D is retired as a reference. Its
clone and directory are gone and it must not be re-cloned. Everything we
took from it still stands and is written down -- the FSplitNESW terrain
split constants, the 0xF61C movement packet layout, the finding that a
client need not compute terrain Z itself -- so CLAUDE.md's reference list,
its hierarchy table, and the architecture doc's protocol row now point at
docs/research/2026-04-12-movement-deep-dive.md rather than erasing the
history. The reference count drops from six to five.

Core tests 3907 passed / 2 skipped.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/plans/2026-07-29-post-vulkan-work-intake.md

@@ -20,6 +20,7 @@ once Campaign V closes.
 | **VERIFY all enums** — **DONE 2026-07-29**, see [`docs/research/2026-07-29-enum-verification-campaign.md`](../research/2026-07-29-enum-verification-campaign.md) | The 2026-06-04 divergence note turned out to be missing from the repo entirely (open question 1 in the successor), so the sweep was regenerated from scratch. | Seven `Property*` tables created (864 members); `DamageType` and `ItemType` value bugs fixed; equipment/physics/item families closed against retail. Twelve open questions remain, headed by five empty `references/` repos. |
 | **Verify networking stack** | `docs/research/2026-06-04-wire-message-catalog.md`: 256 opcodes catalogued, 114 parsed. | Audit parsed-vs-stub-vs-missing against the catalog; prioritize by what live servers actually send (Coldeve session logs are now a real corpus); holtburger remains the client-side oracle. |
 | **Physics review — retail landing bounce et al.** | The named-retail decomp workflow; carried debt #116 (slide response), TS-50/51/53 in the divergence register. | A focused fidelity pass: start with the user's observed case — long-jump landing should bounce/recoil as retail does (grep `named-retail` for the landing/impact path in `MovementManager`/`SetMotion` land states before writing anything). Each fix follows grep→decompile→pseudocode→port→conformance. |
+| **Audio fidelity review** — user-sourced, 2026-07-29 | User reports sound "not working that good" generally. `AudioHookSink` + `OpenAlAudioEngine` are the current path; `SoundId` now carries retail's full 205-entry `SoundType` table (adopted 2026-07-29), so the catalog is no longer the gap. | Scope: sound *triggering*, *selection*, and *attenuation* versus retail — which hooks fire, how a SoundTable entry is chosen among its probability-weighted alternatives, and the falloff/pan curve. Separate from the `SoundId` catalog adoption, which was naming only. Oracles: named-retail's sound path, ACE, and the DAT SoundTable. |
 
 ## C. New feature bodies — milestone candidates, no existing spec