api: load wildpc.yaml once per listing, not once per item

/services and /jobs called get_wildpc_root() + load_config() *inside* the
loop over registry.all(), so every item paid a full reparse of wildpc.yaml
and all 77 program/deployment YAMLs (~55ms registry + ~103ms config). With
38 services and 12 jobs on this node that was 6.8s and 3.0s per request,
uncached — the dashboard's /services and /scheduled pages each fire one of
these plus /status, which is where their >10s load came from.

Hoist the load to a single _try_load_config() call per request; the source
backfill and the non-deployed pass both read that one config. Responses are
byte-identical to before; both endpoints now serve in ~0.27s.

wildpc-api/src/wildpc_api/routes.py

@@ -233,6 +233,23 @@ def _make_systemd_info(name: str, timer: bool = False) -> SystemdInfo:
     return SystemdInfo(unit_name=unit_name, unit_path=unit_path, timer=timer)
 
 
+def _try_load_config(root: Path | None) -> object | None:
+    """Load wildpc.yaml for `root`, or None when there's no config to read.
+
+    Listing endpoints call this **once** and reuse the result: load_config()
+    reparses every program/deployment YAML, so a per-item load turns a listing
+    into an N x full-config-parse (seconds, not milliseconds).
+    """
+    if root is None:
+        return None
+    from wildpc_core.config import load_config
+
+    try:
+        return load_config(root)
+    except FileNotFoundError:
+        return None
+
+
 def _backfill_source(name: str, config: object) -> str | None:
     """Resolve source path from program ref in config."""
     if name in config.programs:
@@ -429,6 +446,10 @@ def list_services(include_remote: bool = False) -> list[ServiceSummary]:
     summaries: list[ServiceSummary] = []
     seen: set[str] = set()
 
+    # One config load for the whole listing — the source backfill and the
+    # non-deployed pass below both read it.
+    config = _try_load_config(get_wildpc_root())
+
     # Services page shows services (systemd) AND statics (caddy) — both are
     # exposed, URL-reachable "services". Not jobs, tools, or remotes.
     for _kind, name, deployed in registry.all():
@@ -437,33 +458,19 @@ def list_services(include_remote: bool = False) -> list[ServiceSummary]:
         s = _service_from_deployed(name, deployed)
         s.node = hostname
         # Backfill source
-        root = get_wildpc_root()
-        if root and s.source is None:
-            try:
-                from wildpc_core.config import load_config
-
-                config = load_config(root)
-                s.source = _backfill_source(name, config)
-            except FileNotFoundError:
-                pass
+        if config is not None and s.source is None:
+            s.source = _backfill_source(name, config)
         summaries.append(s)
         seen.add(name)
 
     # Non-deployed from wildpc.yaml
-    root = get_wildpc_root()
-    if root:
-        try:
-            from wildpc_core.config import load_config
-
-            config = load_config(root)
-            for name, svc in config.services.items():
-                if name not in seen:
-                    s = _service_from_spec(name, svc, config)
-                    s.node = hostname
-                    summaries.append(s)
-                    seen.add(name)
-        except FileNotFoundError:
-            pass
+    if config is not None:
+        for name, svc in config.services.items():
+            if name not in seen:
+                s = _service_from_spec(name, svc, config)
+                s.node = hostname
+                summaries.append(s)
+                seen.add(name)
 
     # Remote
     if include_remote:
@@ -553,39 +560,28 @@ def list_jobs(include_remote: bool = False) -> list[JobSummary]:
     summaries: list[JobSummary] = []
     seen: set[str] = set()
 
+    # One config load for the whole listing (see list_services).
+    config = _try_load_config(get_wildpc_root())
+
     # Deployed jobs (scheduled)
     for _kind, name, deployed in registry.all():
         if not deployed.schedule:
             continue
         s = _job_from_deployed(name, deployed)
         s.node = hostname
-        root = get_wildpc_root()
-        if root and s.source is None:
-            try:
-                from wildpc_core.config import load_config
-
-                config = load_config(root)
-                s.source = _backfill_source(name, config)
-            except FileNotFoundError:
-                pass
+        if config is not None and s.source is None:
+            s.source = _backfill_source(name, config)
         summaries.append(s)
         seen.add(name)
 
     # Non-deployed from wildpc.yaml
-    root = get_wildpc_root()
-    if root:
-        try:
-            from wildpc_core.config import load_config
-
-            config = load_config(root)
-            for name, job in config.jobs.items():
-                if name not in seen:
-                    s = _job_from_spec(name, job, config)
-                    s.node = hostname
-                    summaries.append(s)
-                    seen.add(name)
-        except FileNotFoundError:
-            pass
+    if config is not None:
+        for name, job in config.jobs.items():
+            if name not in seen:
+                s = _job_from_spec(name, job, config)
+                s.node = hostname
+                summaries.append(s)
+                seen.add(name)
 
     # Remote
     if include_remote: