[FEATURE] Agent view should not auto-complete sessions — require manual completion or archive

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Sessions in agent view move to the "Completed" group the moment the agent finishes a turn without hitting a permission prompt or explicit question. The problem is this makes it impossible to tell which sessions are truly finished versus which ones I just haven't responded to yet.

Example: I dispatched a session asking "what is my name?" and it resolved the answer from git config, then went straight to Completed. From the table, that looks identical to a session that finished a multi-file refactor and genuinely has nothing left to do. When running several sessions in parallel, I lose track of which ones I'm still mid-conversation with.

"Completed" is conflating two things:

1. The session finished its work, I don't need to look at it again
2. The session responded, but I haven't decided whether I'm done with it

Proposed Solution

Two options that would both fix this:

Option A: Default to "Needs input," require manual completion.
Every session that finishes a turn stays in "Needs input" (or similar active state) until the user explicitly marks it done. Could be a keybinding like Ctrl+D or running /stop. This treats conversations as open until the user says otherwise.

Option B: Add an "Archive" action.
Keep the current auto-complete behavior, but add a way to archive sessions you're truly done with. Unarchived sessions in Completed are implicitly "I haven't looked at this yet." Archived ones collapse into a separate group.

Either way, the core fix is the same: the user needs an intentional gesture to dismiss a session rather than the system deciding for them.

Alternative Solutions

• Peeking (Space) at each Completed session to check if it still needs attention, but that doesn't scale
• Pinning (Ctrl+T) sessions I expect to continue, which helps visibility but doesn't communicate state
• The "Idle" (dimmed) state documented in the agent view docs could theoretically serve this purpose but doesn't seem to apply here

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI) / Agent view

Use Case Example

1. I dispatch 5 sessions: 3 are tasks (fix bug, write tests, review PR) and 2 are conversations (asking about code, brainstorming an approach)
2. All 5 finish their first turn and land in Completed
3. I have no way to tell which ones I still need to engage with without peeking at each
4. With manual completion: all 5 stay active until I review and dismiss them
5. With archive: I archive the 3 finished tasks after reviewing their output, the 2 conversations stay visible as unarchived

Additional Context

Even for task-oriented sessions, auto-completing removes the opportunity to verify work before dismissing it. A manual completion gesture would double as a lightweight review checkpoint.