feat(hosts): per-host tags edit + dashboard chip-row filter (P4-07)

web/templates/partials/host_chrome.html

@@ -39,7 +39,13 @@
           <span class="dot dot-failed"></span>
         {{end}}
         <h1 class="mono text-[26px] font-medium tracking-[0.005em] text-ink">{{$host.Name}}</h1>
-        <div class="flex gap-1.5">{{range $host.Tags}}<span class="tag">{{.}}</span>{{end}}</div>
+        <div class="flex gap-1.5 items-center">
+          {{range $host.Tags}}<a href="/?tag={{.}}" class="tag" title="filter dashboard by this tag">{{.}}</a>{{end}}
+          <button type="button" class="text-ink-fade text-[11px] hover:text-ink-mid"
+                  style="padding: 2px 6px; border: 1px dashed var(--line); border-radius: 3px; cursor: pointer;"
+                  onclick="document.getElementById('tags-edit-{{$host.ID}}').classList.toggle('hidden')"
+                  title="Edit tags">+ tag</button>
+        </div>
         {{if gt $page.ScheduleVersion 0}}
           <span class="mono text-[11px] text-ink-mute ml-2">
             version {{$page.ScheduleVersion}}
@@ -51,6 +57,22 @@
           </span>
         {{end}}
       </div>
+      {{/* Inline tags editor — hidden by default; toggled by the "+ tag"
+           button above. Comma-separated input with autocomplete sourced
+           from the fleet's distinct tags via a <datalist>. */}}
+      <form id="tags-edit-{{$host.ID}}" method="post"
+            action="/hosts/{{$host.ID}}/tags"
+            class="hidden mt-3 flex items-center gap-2">
+        <input type="text" name="tags" class="field mono text-[12px]"
+               style="max-width: 480px;"
+               value="{{joinComma $host.Tags}}"
+               list="known-tags"
+               placeholder="comma-separated · e.g. prod, london, db" />
+        <datalist id="known-tags">
+          {{range $page.KnownTags}}<option value="{{.}}">{{end}}
+        </datalist>
+        <button type="submit" class="btn btn-primary">Save tags</button>
+      </form>
       <div class="flex items-center gap-3 mt-3 text-[13px] text-ink-mute">
         <span class="mono text-ink-mid">{{$host.OS}}/{{$host.Arch}}</span>
         <span class="text-ink-fade">·</span>