feat(web): keep the four info cards, enrich them, drop the status-header tiles

The dashboard used to open with six status-header tiles *and* four compact
cards restating them (runner state lived in three places at once). The tiles
are gone; each card is now the single owner of its subject, enriched with
what only the tiles had (CPU%/RAM/disk with gauges) plus what neither had
(hostname, kernel, full CPU model, the vmware-host.service row).

All four cards share the same <dl> grammar and font scale now -- VMware and
Runners were a bordered <table> at a different size/case, which read as a
visibly different style sitting next to Host and Cargo cache's plain
label/value lists.

operations/host.py also gains delete_template()/TemplateDeleteResult, used
by the template-delete route in the next commit.

tests/python/test_host_resources.py

@@ -40,6 +40,19 @@ _MEMINFO = (
 _UPTIME = "123456.78 987654.32\n"
 _LOADAVG = "0.50 0.75 1.00 3/456 7890\n"
 
+# Two cores' worth of /proc/cpuinfo -- the parser takes the FIRST "model name".
+_CPUINFO = (
+    "processor\t: 0\n"
+    "vendor_id\t: GenuineIntel\n"
+    "model name\t: Intel(R) Core(TM) i9-13900K CPU @ 3.00GHz\n"
+    "cache size\t: 36864 KB\n"
+    "\n"
+    "processor\t: 1\n"
+    "model name\t: Intel(R) Core(TM) i9-13900K CPU @ 3.00GHz\n"
+)
+_OSRELEASE = "7.0.0-28-generic\n"
+_HOSTNAME = "ci-host\n"
+
 
 def _fake_reader(calls: dict[str, int]) -> Any:
     def _read(path: str) -> str:
@@ -52,6 +65,12 @@ def _fake_reader(calls: dict[str, int]) -> Any:
             return _UPTIME
         if path == "/proc/loadavg":
             return _LOADAVG
+        if path == "/proc/cpuinfo":
+            return _CPUINFO
+        if path == "/proc/sys/kernel/osrelease":
+            return _OSRELEASE
+        if path == "/proc/sys/kernel/hostname":
+            return _HOSTNAME
         raise AssertionError(f"unexpected proc path: {path}")
 
     return _read
@@ -113,6 +132,61 @@ def test_host_resources_uptime_and_loadavg(monkeypatch: pytest.MonkeyPatch) -> N
     assert result.load15 == pytest.approx(1.00)
 
 
+# ── host_resources: static identity fields (CPU model, kernel, hostname) ─────
+
+
+def test_host_resources_reports_cpu_model_kernel_and_hostname(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    _install_fake_proc(monkeypatch)
+
+    result = host_resources()
+
+    assert result.cpu_model == "Intel(R) Core(TM) i9-13900K CPU @ 3.00GHz"
+    assert result.kernel == "7.0.0-28-generic"
+    assert result.hostname == "ci-host"
+
+
+def test_host_resources_cpu_model_is_empty_when_cpuinfo_has_no_model_name(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Not every architecture prints ``model name`` (e.g. arm64) -- degrade, don't crash."""
+    calls: dict[str, int] = {}
+    inner = _fake_reader(calls)
+
+    def _read(path: str) -> str:
+        if path == "/proc/cpuinfo":
+            return "processor\t: 0\nBogoMIPS\t: 50.00\n"
+        return str(inner(path))
+
+    monkeypatch.setattr(host_module, "_read_proc", _read)
+    monkeypatch.setattr(host_module.time, "sleep", lambda _s: None)
+
+    assert host_resources().cpu_model == ""
+
+
+def test_host_resources_unreadable_static_fields_do_not_zero_live_metrics(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """A missing ``/proc/cpuinfo`` must not cost us CPU%/RAM/load as well."""
+    calls: dict[str, int] = {}
+    inner = _fake_reader(calls)
+
+    def _read(path: str) -> str:
+        if path in ("/proc/cpuinfo", "/proc/sys/kernel/osrelease", "/proc/sys/kernel/hostname"):
+            raise OSError("gone")
+        return str(inner(path))
+
+    monkeypatch.setattr(host_module, "_read_proc", _read)
+    monkeypatch.setattr(host_module.time, "sleep", lambda _s: None)
+
+    result = host_resources()
+
+    assert result.cpu_pct == pytest.approx(50.0)
+    assert result.load1 == pytest.approx(0.50)
+    assert (result.cpu_model, result.kernel, result.hostname) == ("", "", "")
+
+
 # ── host_resources: degrade to zeros on OSError, never raise ────────────────
 
 
@@ -134,6 +208,9 @@ def test_host_resources_degrades_to_zeros_on_oserror(monkeypatch: pytest.MonkeyP
         load1=0.0,
         load5=0.0,
         load15=0.0,
+        cpu_model="",
+        kernel="",
+        hostname="",
     )
 
 
@@ -144,6 +221,8 @@ def test_host_resources_degrades_to_zeros_when_second_stat_sample_fails(
     calls = {"n": 0}
 
     def _flaky(path: str) -> str:
+        if path.startswith("/proc/sys/kernel/") or path == "/proc/cpuinfo":
+            return ""  # static identity reads happen before the live-metric block
         if path != "/proc/stat":
             raise AssertionError("should not reach meminfo after stat blows up")
         calls["n"] += 1