chore: add migration/ bundle for cross-machine setup

Bundles state that lives OUTSIDE the xenia-rs repo so a fresh clone on
another machine can be brought up to identical configuration via
migration/setup.sh:

  - claude-memory/             ~/.claude/projects/-home-fabi-RE-Project-Sylpheed/memory/
                               (103 files, 1.1 MB - MEMORY.md + every
                                project_xenia_rs_*.md from audits
                                addis_signext through audit-058)
  - project-root/dot-claude/   <project-root>/.claude/settings.json
                               (Stop hook + permissions)
  - project-root/ppc-manual/   <project-root>/ppc-manual/
                               (PowerPC reference docs, 397 files, 3.7 MB)
  - project-root/run-canary.sh <project-root>/run-canary.sh
  - README.md                  Human-readable setup checklist
  - setup.sh                   Idempotent installer (also reclones
                               xenia-canary at pinned HEAD 6de80dffe)
  - MANIFEST.md                Per-file mapping + per-file-not-bundled
                               restoration recipe

Excluded from bundle (not shippable via git):
  - Sylpheed ISO (7.8 GB; copyright; manual copy required)
  - sylpheed.db (395 MB; regenerable from XEX via analysis tooling)
  - target/ build artifacts (rebuild on target)
  - audit-runs probe firehoses (.log/.stdout/.stderr ~11 GB; rerun if needed)
  - audit-runs memory dumps (.bin ~4.5 GB; rerun audit-026/027/029 if needed)
  - xenia-canary checkout (setup.sh reclones from
    git.mc02.dev/fabi/Xenia-Canary.git at HEAD 6de80dffe)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

migration/project-root/ppc-manual/memory/sthbrx.md

@@ -0,0 +1,131 @@
+# `sthbrx` — Store Half Word Byte-Reverse Indexed
+
+> **Category:** [Memory](../categories/memory.md) · **Form:** [X](../forms/X.md) · **Opcode:** `0x7c00072c`
+
+<!-- GENERATED: BEGIN -->
+
+## Assembler Mnemonics
+
+| Mnemonic | XML entry | Flags | Description |
+| --- | --- | --- | --- |
+| `sthbrx` | `sthbrx` | — | Store Half Word Byte-Reverse Indexed |
+
+## Syntax
+
+```asm
+sthbrx [RS], [RA0], [RB]
+```
+
+## Encoding
+
+### `sthbrx` — form `X`
+
+- **Opcode word:** `0x7c00072c`
+- **Primary opcode (bits 0–5):** `31`
+- **Extended opcode:** `918`
+- **Synchronising:** no
+
+| Bits | Field | Meaning |
+| --- | --- | --- |
+| 0–5 | `OPCD` | primary opcode |
+| 6–10 | `RT/FRT/VRT` | destination |
+| 11–15 | `RA/FRA/VRA` | source A |
+| 16–20 | `RB/FRB/VRB` | source B |
+| 21–30 | `XO` | extended opcode (10 bits) |
+| 31 | `Rc` | record-form flag |
+
+## Operands
+
+| Field | Role | Description |
+| --- | --- | --- |
+| `RS` | sthbrx: read | Source GPR (alias for RD in some stores). |
+| `RA0` | sthbrx: read | Source GPR; when the encoded register number is 0 the operand is the literal 64-bit zero, **not** `r0`. |
+| `RB` | sthbrx: read | Source GPR. |
+
+## Register Effects
+
+### `sthbrx`
+
+- **Reads (always):** `RS`, `RA0`, `RB`
+- **Reads (conditional):** _none_
+- **Writes (always):** _none_
+- **Writes (conditional):** _none_
+
+## Status-Register Effects
+
+_No condition-register or status-register effects._
+
+## Operation (pseudocode)
+
+```
+; Pseudocode derives directly from the xenia-rs interpreter
+; arm (see Implementation References). Operation semantics:
+;   - Read source operands from the fields listed under Operands.
+;   - Apply the arithmetic / logical / memory action described
+;     in the Description field above.
+;   - Write results to the destination register(s); update any
+;     status bits enumerated under Status-Register Effects.
+; Consult the IBM AIX reference link under IBM Reference for
+; canonical PPC-style pseudocode where xenia's expression is
+; terse.
+```
+
+## C Translation Example
+
+```c
+/* C translation: the xenia-rs interpreter arm below in           */
+/* Implementation References is the authoritative semantic        */
+/* snapshot. Translate it line-by-line:                            */
+/*   - ctx.gpr[N]  -> r[N]       (or f[]/v[] for FPRs/VRs)        */
+/*   - mem.read_u*/write_u* -> mem_read_u*_be / mem_write_u*_be   */
+/*   - ctx.update_cr_signed(fld, v) -> update_cr_signed(fld, v)   */
+/*   - ctx.xer_ca / xer_ov / xer_so -> xer.CA / xer.OV / xer.SO   */
+/* The Register Effects and Status-Register Effects tables above  */
+/* enumerate every side effect a faithful translation must emit.  */
+```
+
+## Implementation References
+
+**`sthbrx`**
+- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="sthbrx"`](../../xenia-canary/tools/ppc-instructions.xml)
+- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_memory.cc:667`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_memory.cc#L667)
+- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:73`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L73)
+- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:846`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L846)
+- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:1822-1830`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L1822-L1830)
+<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
+
+```rust
+        PpcOpcode::sthbrx => {
+            let ea = if instr.ra() == 0 { 0u64 } else { ctx.gpr[instr.ra()] };
+            let ea = ea.wrapping_add(ctx.gpr[instr.rb()]) as u32;
+            if let Some(t) = ctx.reservation_table.as_ref().filter(|t| t.is_enabled()) {
+                if t.has_active_reservers() { t.invalidate_for_write(ea); }
+            }
+            mem.write_u16(ea, (ctx.gpr[instr.rs()] as u16).swap_bytes());
+            ctx.pc += 4;
+        }
+```
+</details>
+
+<!-- GENERATED: END -->
+
+## Special Cases & Edge Conditions
+
+- **Writes little-endian half.** Takes the low 16 bits of `RS`, swaps the two bytes, writes them at `EA`. After execution, byte at `EA` is `RS[56:63]` (low byte) and byte at `EA+1` is `RS[48:55]` (high byte). The xenia snapshot does `(ctx.gpr[instr.rs()] as u16).swap_bytes()`.
+- **Used to emit little-endian half-words.** Symmetric counterpart of [`lhbrx`](lhbrx.md). Common in PNG / ZIP / RIFF chunk emit paths.
+- **High bits of `RS` ignored.** Storing a 64-bit value through `sthbrx` truncates and reverses only the low half-word; the high 48 bits are not consulted.
+- **X-form only — no D-form, no update form.** Only the indexed form exists. `EA = (RA|0) + RB`.
+- **`RA0` semantics.** When `RA = 0`, base is literal zero; `sthbrx RS, 0, RB` writes at exact `RB`.
+- **Alignment.** Hardware tolerates unaligned half-word writes; cache-inhibited storage may raise alignment exceptions on real hardware.
+- **No CR / FPSCR effects.**
+
+## Related Instructions
+
+- [`lhbrx`](lhbrx.md) — load-half byte-reverse (matching load).
+- [`stwbrx`](stwbrx.md), [`stdbrx`](stdbrx.md) — wider byte-reverse stores.
+- [`sth`](sth.md), [`sthx`](sth.md) — non-reversing half stores.
+
+## IBM Reference
+
+- [AIX 7.3 — `sthbrx` (Store Half Byte-Reverse Indexed)](https://www.ibm.com/docs/en/aix/7.3.0?topic=set-sthbrx-store-half-byte-reverse-indexed-instruction)
+- `PowerISA v2.07B Book II` § "Byte-Reverse Storage Access".