refactor(net): own live session composition

Extract reset, selection, entered-world, and route construction behind LiveSessionHost while preserving the sole LiveSessionController authority. Retain partial route and subscription cleanup for retry, and replace the embedded ACE-only shortcut with the exact named-retail unsigned skill formula.

Co-authored-by: Codex <codex@openai.com>

docs/ISSUES.md

@@ -27,9 +27,11 @@ What does NOT go here:
 ## Current queue — 2026-07-22
 
 - **Active structural work:** `GameWindow` decomposition. Slices 1–7 are
-  complete; `GameWindow.OnUpdate` and `GameWindow.OnRender` are typed
-  orchestration handoffs and the class is 4,666 lines / 196 fields / 70
-  methods. Final Slice 8 composition/shutdown cleanup is active in
+  complete; Slice 8 checkpoints A–C now own native callbacks and live-session
+  composition outside the shell. `GameWindow.OnUpdate` and
+  `GameWindow.OnRender` are typed orchestration handoffs and the class is 4,589
+  lines / 196 fields / 69 methods. Remaining Slice 8 composition/shutdown
+  cleanup is active in
   [`docs/architecture/code-structure.md`](architecture/code-structure.md).
   This is the behavior-preserving prerequisite before new M4 feature bodies.
 - **Connected-gate fidelity:** `#232` adds canonical managed/GPU/cache-owner
@@ -73,6 +75,39 @@ Copy this block when adding a new issue:
 
 ---
 
+## #233 — Live skill-credit resolver used an ACE shortcut, not retail's formula
+
+**Status:** DONE (2026-07-22, GameWindow Slice 8 Checkpoint C)
+**Severity:** MEDIUM
+**Filed:** 2026-07-22
+**Component:** live character state / DAT skill formulas
+
+**Description:** The live skill-update route calculated a skill's primary-
+attribute contribution with an ACE-oriented shortcut. It rejected every
+formula whose first multiplier was zero, truncated division, and added `W`
+after division. Custom DAT formulas—and any stock boundary landing on a half—
+could therefore display the wrong skill value.
+
+**Root cause / status:** The binding cited ACE without first checking named
+retail. `SkillFormula::Calculate @ 0x00591960` treats all four arithmetic words
+as unsigned, fails only for `Z == 0`, forms the wrapping numerator
+`X*a + Y*b + W`, and rounds `numerator/Z` half-up. Checkpoint C moved that
+algorithm into `RetailSkillFormula`, added a named `LiveSkillCreditResolver`,
+and pinned zero-X, W placement, half rounding, unsigned reinterpretation, and
+32-bit wrap with conformance tests.
+
+**Files:** `src/AcDream.App/Net/RetailSkillFormula.cs`;
+`tests/AcDream.App.Tests/Net/RetailSkillFormulaTests.cs`.
+
+**Research:**
+[`docs/research/skill_formula_calculate_pseudocode.md`](research/skill_formula_calculate_pseudocode.md).
+
+**Acceptance:** Live skill updates resolve the DAT entry and reproduce the
+named retail function for all unsigned field values; missing skills or
+attributes remain safely projected as zero.
+
+---
+
 ## #232 — Nine-stop soak process-memory gate lacks canonical owner snapshots
 
 **Status:** OPEN