docs(explore-notes): document interactive session id persistence and resume precedence

docs/explore-notes/conpty-sessions.md

@@ -1,7 +1,7 @@
 # ConPTY interactive sessions & launch specs
 
 > **Explore-note — verify before trusting.** Distilled map of a subsystem, not authoritative.
-> Last verified against commit `aac84e4` (2026-08-06).
+> Last verified against commit `1a988ff` (2026-08-06).
 > Drift check: `git log --oneline bdee731..HEAD -- src/ClaudeDo.Worker/Planning src/ClaudeDo.Worker/Hub src/ClaudeDo.Worker/Runner/ClaudeArgsBuilder.cs src/ClaudeDo.Ui/ViewModels/MissionControlViewModel.cs src/ClaudeDo.Ui/Views/InteractiveTerminalView.axaml`
 > Stable structure only (no line numbers). See docs/explore-notes/README.md.
 
@@ -35,7 +35,7 @@ Two independent reasons:
 
 A fresh task session's brief lives at `~/.todo-app/task-sessions/<taskId>/brief.md`
 (`InteractiveLaunchSpecService.BuildFreshTaskArgsAsync`). A task with neither title nor
-description skips the file **and** the positional arg entirely.
+description skips the file **and** the positional arg entirely — it still gets `--session-id`.
 
 ## Argument ordering
 
@@ -46,6 +46,34 @@ except for a fresh task session with a brief, where `--add-dir <sessionDir>` mus
 `--model` is deliberately **NOT** forced on an interactive session — the user can still switch
 models in the TUI.
 
+## Resuming a task session (`TaskEntity.InteractiveSessionId`)
+
+`claude --session-id <uuid>` lets the caller pre-assign a conversation's session id instead of
+waiting for the CLI to generate one. `BuildForTaskAsync` uses this so a closed or aborted
+interactive task session can be resumed even if it never got far enough to write anything to its
+own transcript:
+
+1. **Resume check.** If the task isn't on a freshly (re)created worktree, `BuildForTaskAsync`
+   picks a session to resume with `task.InteractiveSessionId ?? run?.SessionId` — this task's own
+   last *interactive* conversation takes precedence over the latest *autonomous* run's session,
+   since they're distinct conversations even against the same worktree. A task that has only ever
+   run autonomously still resumes into that run's session the first time it's opened interactively
+   (this is the pre-existing behavior `run?.SessionId` alone used to provide).
+2. **Fresh path.** If neither is available (never run any way, or `isFreshWorktree`), a new
+   `Guid.NewGuid()` is generated and persisted to `TaskEntity.InteractiveSessionId` via
+   `TaskRepository.SetInteractiveSessionIdAsync` — **before** the `LaunchSpec` is returned, i.e.
+   before the ConPTY host ever spawns `claude`. `BuildFreshTaskArgsAsync` then passes it as
+   `--session-id <guid>`, placed as the single-value flag directly before the positional kickoff
+   (or, with no brief, right after `--effort`).
+3. **Fresh worktree wins.** `isFreshWorktree` forces `run` to `null` *and* is checked before
+   reading `task.InteractiveSessionId`, so a recreated worktree never resumes a stale id from
+   either source — it always takes the fresh path, which overwrites the stale
+   `InteractiveSessionId` with the new one.
+
+Net effect: reopening an interactive session for a task (pane closed, process killed, whatever)
+resumes the same claude conversation, because the id was committed to the DB before the previous
+launch even started.
+
 ## List handler ("Let Claude handle it")
 
 `BuildForMergeHelperAsync` uses `--permission-mode auto` so it runs unattended. The