refactor(maestro): flatten web UI to a single host

Session tree nests by working directory only; the daemon chips in the
header become a session tally, and the spawn form loses its host picker.
API calls move from /api/daemons/:id/* to /api/dirs, /api/recent-dirs,
/api/gitroot, and /api/info.

web/src/styles.css

@@ -625,7 +625,7 @@ textarea {
   box-shadow: 0 0 0 3px var(--accent-tint);
 }
 
-/* ---------- daemon / status bar ---------- */
+/* ---------- status bar ---------- */
 
 .statusbar {
   display: flex;
@@ -645,28 +645,14 @@ textarea {
   min-width: var(--sp-2);
 }
 
-.daemons {
-  display: inline-flex;
-  flex-wrap: wrap;
-  justify-content: flex-end;
-  gap: var(--sp-2);
-  align-items: center;
-  min-width: 0;
-}
-
-.daemon-chip {
+.session-tally {
   display: inline-flex;
   align-items: center;
-  gap: 6px;
-  background: var(--surface-2);
-  border: 1px solid var(--border);
-  border-radius: var(--r-pill);
-  padding: 3px var(--sp-2) 3px var(--sp-2);
-  font-size: var(--fs-12);
-  color: var(--ink);
+  gap: 7px;
+  font-variant-numeric: tabular-nums;
 }
 
-.daemon-chip::before {
+.session-tally::before {
   content: "";
   width: 6px;
   height: 6px;
@@ -675,42 +661,6 @@ textarea {
   box-shadow: 0 0 5px var(--live-glow);
 }
 
-/* Green session count baked into each host chip (replaces the global tally). */
-.daemon-count {
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  min-width: 17px;
-  height: 17px;
-  padding: 0 5px;
-  border-radius: var(--r-pill);
-  font-size: var(--fs-11);
-  font-weight: 600;
-  font-variant-numeric: tabular-nums;
-  color: var(--live);
-  background: color-mix(in srgb, var(--live) 16%, transparent);
-}
-
-.daemon-count.is-empty {
-  color: var(--muted);
-  background: var(--surface-2);
-}
-
-.daemon-empty {
-  display: inline-flex;
-  align-items: center;
-  gap: 7px;
-  color: var(--muted);
-}
-
-.daemon-empty::before {
-  content: "";
-  width: 6px;
-  height: 6px;
-  border-radius: 50%;
-  background: var(--warn);
-}
-
 /* ---------- session tree ---------- */
 
 .tree {
@@ -863,16 +813,6 @@ textarea {
   gap: var(--sp-2);
 }
 
-.leaf-daemon {
-  color: var(--faint);
-  flex: 0 0 auto;
-}
-
-.leaf-daemon::before {
-  content: "@";
-  opacity: 0.6;
-}
-
 .leaf-cmd {
   color: var(--muted);
   overflow: hidden;
@@ -995,11 +935,6 @@ textarea {
   margin-top: var(--sp-2);
 }
 
-.empty.connecting .empty-glyph {
-  color: var(--warn);
-  animation: pulse 1.6s var(--ease-out) infinite;
-}
-
 /* ---------- attach view ---------- */
 
 .attach {
@@ -1803,14 +1738,9 @@ textarea {
     max-width: none;
     order: -1;
   }
-  /* daemons drop to their own full-width wrapped line; no side overflow */
   .statusbar .spacer {
     display: none;
   }
-  .daemons {
-    flex: 1 1 100%;
-    justify-content: flex-start;
-  }
   .tree-leaf .leaf-actions {
     opacity: 1;
   }