feat: add durable AgentOS slice execution

docs/slices.md

@@ -211,16 +211,18 @@ Zopu implements one approved slice in an isolated repository environment and str
 Initial adapter choice:
 
 ```text
-SandboxRuntime = CubeSandboxLive
-HarnessRuntime = OmpHarnessLive (or one chosen harness)
+SandboxRuntime = AgentOsSandboxLive
+HarnessRuntime = CodexHarnessLive
+Durable orchestration = Convex Workflow
 ```
 
 Flow:
 
 ```text
-prepare worktree
-→ create sandbox
-→ clone/mount repo
+load the project's authenticated Git connection
+→ start durable Convex workflow
+→ create AgentOS execution environment
+→ clone the single configured repo
 → inject context
 → run one slice
 → normalize events
@@ -230,14 +232,15 @@ prepare worktree
 
 Security:
 
-- scoped Git/model tokens;
+- GitHub OAuth or self-hosted Gitea PAT, scoped to one project;
+- scoped Git/model tokens passed only to private execution;
 - isolated HOME/worktree;
 - one mutating attempt per worktree;
 - timeout/cancel cleanup.
 
 ### Frontend
 
-Current activity, changed files, artifact links, expandable raw logs.
+Project selector/settings, Git connection status, current activity, changed files, artifact links, expandable raw logs, cancel/retry, and manual Git delivery controls.
 
 ### Acceptance
 
@@ -247,6 +250,8 @@ Current activity, changed files, artifact links, expandable raw logs.
 - provider failure becomes classified attempt outcome;
 - exact base/candidate revision recorded.
 
+Rivet Engine coordinates AgentOS actor placement through a normal runner, but does not own product orchestration; Convex Workflow remains canonical for the Run lifecycle. Cube/Kubernetes sandbox support remains behind `SandboxRuntime` and can be mounted through AgentOS incrementally.
+
 ---
 
 ## Slice 6 — Independent verification and repair
@@ -490,4 +495,4 @@ browser-tester integration-coordinator
 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12
 ```
 
-Parallel engineering is allowed *within* a slice after contracts land, but product release order remains sequential.
+Parallel engineering is allowed _within_ a slice after contracts land, but product release order remains sequential.