tui: surface current sort + tighten profile/group display in list title

[njbrake]

Note: this issue was drafted by Claude via back-and-forth with @njbrake. The reasoning and decisions are his; the prose is Claude's.

Background

The home view's list-pane title currently reads, e.g.:

 Agent of Empires [all] (by project) 

Two small UX issues with how this header surfaces mode state.

1. Current sort order is hidden

o cycles sort order forward, Ctrl-O reverses, through Newest → Recent → Oldest → A-Z → Z-A. The selected value is persisted in config.app_state.sort_order, but the only place it shows up is the help overlay (? opens it; the help renders (current sort: Recent) near the keybind list).

That means after restart, you can't tell which sort mode is active without opening help. Group mode does the right thing; sort should follow the same pattern.

Proposal: put the active sort label inline with the existing (by project) suffix in the list title, e.g.:

 Agent of Empires [my-profile] (by project, sort: Recent) 

When sort is the default Newest, omit the suffix to keep noise low. Only show non-default values, same way the group suffix only shows when in Project mode.

Implementation surface, by file:

• src/session/config.rs already has SortOrder::label() returning the user-facing string.
• src/tui/home/render.rs:305-322 is where the title is composed; just append a sort suffix the same way group_suffix works.

2. [all] profile tag is noise

active_profile_display() (src/tui/home/mod.rs:1224) returns "all" when no profile filter is active. That is the default state for most users, so the header reads Agent of Empires [all] the vast majority of the time.

Proposal: when the profile filter is the default (no filter applied), drop the [...] segment entirely. Only render the bracketed profile tag when an explicit filter is active. The bracket then doubles as the visual indicator that you have a filter on, which is the only time the user actually needs to know.

Implementation surface:

• active_profile_display() keeps returning Option<&str> shape (or returns &str as today and the caller checks); the title-construction site at render.rs:312-321 conditionally formats " [{}]" only when present.

Out of scope

• No new keybind to set sort directly (just the existing o / Ctrl-O cycle).
• No status-bar real estate changes; this is title-bar only.
• No web dashboard changes.

Acceptance

• After restart, the list pane title shows the active sort when it is non-default.
• The [all] tag never appears; [<profile>] appears only when a real filter is in effect.
• Profile picker and :profile switching still update the title in real time.