docs: describe the flat container list, not a dormant tree

mara's ruling on the review: documentation describes functionality as
is. The dashboard doc carried a "Topology tree" section marked dormant,
still spelling out the indent lanes, joints and continuation bars the
renderer paints — for a renderer that, with no parent field to walk,
puts every container at depth 0 and emits no prefix column at all. A
section labelled dormant is still a section describing a feature the
code does not have.

Each one now states what the page renders today: SW4RM's C0NTAINERS is
a flat alphabetical list, one row per container, no indent and no glyph;
the tree section says nothing nests and names the code that decides so;
the selection bar lists the bulk actions it has, without a note about
the M0V3 picker it doesn't (agent-hierarchy.md's removal table is where
that record belongs).

Two more the -U15 context sweep turned up outside that section, neither
naming a removed identifier so neither reachable by grep: approvals.md
told an agent to clone "the child's" config repo, and hivectl.md sold
`agent restart` as a way round "the agent hierarchy".

docs/web-ui/dashboard.md

@@ -56,15 +56,10 @@ surfaces, not tab panes.
 
 ## SW4RM tab
 
-**C0NTAINERS** — live containers rendered as a flat,
-alphabetically-sorted list. The renderer still walks
-`ContainerView.parent` for a depth-first tree with ASCII glyphs
-(`├─`, `└─`, `│  ` continuation columns), but that field no longer
-exists, so every row sits at depth 0 and the renderer paints no glyph. The tree
-sorts alphabetically;
-roots likewise. The tree tolerates cycles in the parent graph —
-it appends orphaned containers (not reachable from any root)
-as roots so no agent disappears. Pulsing red banner at the top
+**C0NTAINERS** — live containers as a flat list, one row per
+container, sorted alphabetically by agent name. No row nests under
+another, none carries an indent or a tree glyph, and every container the
+rescan reports gets a row. Pulsing red banner at the top
 of this section if any two sub-agents hash to the same port
 (`port_conflicts` from `/api/state`): the operator must rename
 one of them and rebuild. `lifecycle::{spawn,rebuild}` also
@@ -981,27 +976,11 @@ identically.)
 
 ### Topology tree
 
-⚠️ **Dormant now that `ContainerView.parent` no longer exists:**
-`buildAgentTree` now puts every container at depth 0 and the rules below are
-all no-ops — the list renders flat. The walk and the prefix painting are
-still in `swarm.js`; retiring them falls to the frontend owner rather
-than to this removal. What follows describes what the code
-still does, for whoever makes that call.
-
-The per-row prefix column (`.tree-prefix`) is **DOM-painted, not
-text-glyph-painted**: each indent lane is its own positioned `<span>`
-so CSS can draw full-height vertical bars that bridge the gap between
-sibling rows. Plain text box-drawing characters (`├─`, `└─`, `│  `)
-would only paint one text-line tall and leave visible breaks between
-the taller-than-one-line container cards, so CSS borders draw the
-bars instead: a continuation bar runs the full height of an
-ancestor's still-open subtree, and the joint at a row's own depth is
-`├` (more siblings below) or `└` (last sibling — the line stops at
-the row's icon midline). Exact lane widths and positioning live in
-`swarm.js`'s tree-prefix rendering and its paired CSS rules — not
-reproduced here since they're tuned in pixel units and will drift.
-With every container at depth 0 these rules are all no-ops and the
-layout reads like a plain flat list, which is what a hive renders today.
+Nothing nests. `swarm.js::buildAgentTree` returns every container at
+depth 0 in alphabetical order, and the row builder emits no prefix
+column for a depth-0 row — so a container row carries no indent, no
+joint and no continuation bar, and the SW4RM list reads as a flat
+roster. The `.tree-prefix` lane rules in `dashboard.css` match nothing.
 
 ## Selection bar
 
@@ -1032,8 +1011,7 @@ frosted-mauve bar slides up from the bottom of the viewport
   - `DESTR0Y` / `PURG3` — always available
 <!-- vale write-good.Passive = YES -->
 
-  The `M0V3` picker that used to sit here no longer exists — an agent
-  has no parent to move it to any more.
+  That list is the whole set — the bar offers no other bulk action.
 - **`✕ clear`** button + `Esc` key clear the entire selection.
 
 Every render prunes stale selections (agents destroyed while