feat: deployment-scoped requires + UI editors, gateway nav, services filter

Model:
- Drop `requires` from ProgramSpec; requires is now deployment-only.
  Collapse Requirement to {ref, bind} with kind defaulting to "deployment"
  (drop the unused `version`). System-package preconditions stay on the
  program as `system_dependencies`, synthesized into {kind: system} for the
  functional check. relations.py/deploy.py read only the deployment's requires.
- create.py seeds a stack's substrate dependency onto the deployment, not the
  program. Docs + tests updated.

UI:
- Add a `requires` editor (useRequires) on service, job, and static detail
  pages — edit service→service deps (ref + optional bind env var).
- Restore the gateway route table "Open" column: a kind-aware in-app link to
  each route's deployment.
- Reformat the reach control: name baked into each option
  (localhost:PORT (local) / <name>.<domain> (internal) / <name>.<pubdomain> (public)).
- Services page: sort statics in with systemd services by name, add a
  search + kind-filter bar mirroring the programs page.

core/tests/test_relations.py

@@ -6,17 +6,18 @@ import pytest
 
 import castle_core.config as C
 from castle_core import relations as R
-from castle_core.manifest import ProgramSpec, Requirement, SystemdDeployment
+from castle_core.manifest import ProgramSpec, SystemdDeployment
 
 
-def _dep(program: str) -> SystemdDeployment:
-    return SystemdDeployment.model_validate(
-        {
-            "manager": "systemd",
-            "program": program,
-            "run": {"launcher": "command", "argv": [program]},
-        }
-    )
+def _dep(program: str, requires: list | None = None) -> SystemdDeployment:
+    spec: dict = {
+        "manager": "systemd",
+        "program": program,
+        "run": {"launcher": "command", "argv": [program]},
+    }
+    if requires is not None:
+        spec["requires"] = requires
+    return SystemdDeployment.model_validate(spec)
 
 
 def _cfg(programs: dict, deployments: dict) -> C.CastleConfig:
@@ -38,20 +39,12 @@ def test_system_dependencies_is_the_system_requirement_alias() -> None:
     assert [(r.kind, r.ref) for r in reqs] == [("system", "pandoc")]
 
 
-def test_requirements_merge_program_and_deployment_deduped() -> None:
-    prog = ProgramSpec(
-        id="web",
-        system_dependencies=["pandoc"],
-        requires=[Requirement(kind="deployment", ref="api", bind="API_URL")],
-    )
-    dep = SystemdDeployment.model_validate(
-        {
-            "manager": "systemd",
-            "program": "web",
-            "run": {"launcher": "command", "argv": ["web"]},
-            "requires": [{"kind": "system", "ref": "pandoc"}],
-        }  # dup of program's
-    )
+def test_requirements_merge_system_deps_and_deployment_requires_deduped() -> None:
+    """The requirement set unions the program's system_dependencies (as {kind: system})
+    with the deployment's own requires, de-duplicated by (kind, ref)."""
+    prog = ProgramSpec(id="web", system_dependencies=["pandoc"])
+    # Two identical deployment requires — deduped to one.
+    dep = _dep("web", requires=[{"ref": "api"}, {"ref": "api"}])
     cfg = _cfg(
         {"web": prog, "api": ProgramSpec(id="api")}, {"web": dep, "api": _dep("api")}
     )
@@ -62,15 +55,13 @@ def test_requirements_merge_program_and_deployment_deduped() -> None:
 def test_deployment_edge_carries_bind_and_counts_fan_in() -> None:
     """A {kind: deployment} requirement becomes an edge (with bind), and the target's
     fan-in is the count of distinct dependents."""
-    consumer = ProgramSpec(
-        id="web", requires=[Requirement(kind="deployment", ref="api", bind="API_URL")]
-    )
-    consumer2 = ProgramSpec(
-        id="cli", requires=[Requirement(kind="deployment", ref="api")]
-    )
     cfg = _cfg(
-        {"web": consumer, "cli": consumer2, "api": ProgramSpec(id="api")},
-        {"web": _dep("web"), "cli": _dep("cli"), "api": _dep("api")},
+        {"web": ProgramSpec(id="web"), "cli": ProgramSpec(id="cli"), "api": ProgramSpec(id="api")},
+        {
+            "web": _dep("web", requires=[{"ref": "api", "bind": "API_URL"}]),
+            "cli": _dep("cli", requires=[{"ref": "api"}]),
+            "api": _dep("api"),
+        },
     )
     m = R.build_model(cfg, check=False)
     edge = next(e for e in m.edges if e.src == "web" and e.dst == "api")
@@ -82,14 +73,10 @@ def test_deployment_edge_carries_bind_and_counts_fan_in() -> None:
 def test_functional_predicate_reports_unmet(monkeypatch: pytest.MonkeyPatch) -> None:
     """`functional?` is derived: a missing system package is unmet; a present
     deployment requirement is satisfied."""
-    prog = ProgramSpec(
-        id="web",
-        system_dependencies=["pandoc"],
-        requires=[Requirement(kind="deployment", ref="api")],
-    )
+    prog = ProgramSpec(id="web", system_dependencies=["pandoc"])
     cfg = _cfg(
         {"web": prog, "api": ProgramSpec(id="api")},
-        {"web": _dep("web"), "api": _dep("api")},
+        {"web": _dep("web", requires=[{"ref": "api"}]), "api": _dep("api")},
     )
     monkeypatch.setattr(R.shutil, "which", lambda _: None)  # not on PATH
     monkeypatch.setattr(R, "_dpkg_installed", lambda _: False)  # nor as a package
@@ -113,8 +100,10 @@ def test_system_requirement_satisfied_by_package_not_on_path(
 
 
 def test_missing_deployment_requirement_is_unmet() -> None:
-    prog = ProgramSpec(id="web", requires=[Requirement(kind="deployment", ref="ghost")])
-    cfg = _cfg({"web": prog}, {"web": _dep("web")})
+    cfg = _cfg(
+        {"web": ProgramSpec(id="web")},
+        {"web": _dep("web", requires=[{"ref": "ghost"}])},
+    )
     m = R.build_model(cfg, check=True)
     web = next(n for n in m.nodes if n.name == "web")
     assert web.unmet == ["deployment:ghost"] and web.functional is False