feat(tiles): each tile header names its harness and model

The tile header is now `● [logo] name · model ..... ⋯ ⤢ ×` (owner request):

- The logo is PR #532's `run-mode-dot <cliId>` slot, so the logos, the skins
  and the plain dot of an id without a logo stay single-sourced in styles.css.
  The id is data (a class and a catalog lookup), never a branch; the frontend
  id-branching guard now also scans constants.js, terminal-split.js and
  tile-grid.js (the one existing shell branch in tile-grid.js, the attach
  route, is allowlisted with its reason).
- The model is the session's displayModel, as text in a data-i18n-skip span
  inside a box whose tooltip may translate. Unknown means the logo alone.
- The logo's tooltip and accessible name say "<harness> · <model>", plus where
  a model the CLI did not report came from ("set at launch", "custom
  endpoint"; zh-CN patterns for both, the names pass through). The model's box
  is aria-hidden so a screen reader hears the model once.
- One painter, _paintSessionHarness (terminal-split.js, shared with the split
  panes next), diffs against what it last wrote, never the DOM: an unchanged
  session writes nothing on a tab render.
- On a narrow header the model gives way first, then the name: the name does
  not shrink at all and is capped at its box, since any shrink factor takes a
  subpixel from a name that fits and ellipsizes it.

The chrome and zoom tests found header parts by child position; they now look
them up by class, with every assertion kept (the rename tests had been passing
against the new logo node by position). The i18n harvester files the logo's
labels as harness and model names that must stay as they are.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/web/public/terminal-split.js

@@ -261,6 +261,39 @@ Object.assign(CodemanApp.prototype, {
   // nothing on the button said which. `.split-open` + aria-pressed give it
   // the same active-state language as the codebase's other toggle buttons
   // (keyboard-accessory's Ctrl key, the voice-input mic).
+  /**
+   * Paints a session header's harness logo and model: a grid tile's, and the
+   * split panes'. The logo is PR #532's `run-mode-dot <cliId>` slot (the id is
+   * data, never a branch), the model is text (describeSessionHarness,
+   * constants.js). Diffs against the values it last wrote, kept on `parts`,
+   * never against the DOM, which the translator may have rewritten: an
+   * unchanged session writes nothing, and this runs on every tab render.
+   *
+   * @param {{harness: HTMLElement, model: HTMLElement, modelName: HTMLElement}} parts - the
+   *   header's nodes (the model's box and the name inside it); the memo lives here too
+   * @param {object} session - the session the header shows
+   * @param {string} logoClass - the header's own class for its logo
+   */
+  _paintSessionHarness(parts, session, logoClass) {
+    const harness = window.CodemanSessionHarness.describeSessionHarness(session, window.__codemanCliCatalog);
+    const cls = `${logoClass} run-mode-dot${harness.id ? ` ${harness.id}` : ''}`;
+    if (parts.harnessClass !== cls) {
+      parts.harnessClass = cls;
+      parts.harness.className = cls;
+    }
+    if (parts.harnessTitle !== harness.title) {
+      parts.harnessTitle = harness.title;
+      parts.harness.title = harness.title;
+      parts.harness.setAttribute('aria-label', harness.title);
+      parts.model.title = harness.title;
+    }
+    if (parts.modelValue !== harness.model) {
+      parts.modelValue = harness.model;
+      parts.modelName.textContent = harness.model;
+      parts.model.hidden = !harness.model;
+    }
+  },
+
   _updateSplitButtonState(open) {
     const btn = document.querySelector('.btn-split');
     if (!btn) return;