Rename Castle -> Wild PC across the repo

Repo-side rename only (Phases 1-3 of the migration plan); the live box
(~/.castle, systemd units, /data/castle, domains) is a separate cutover.

- Slug `castle` -> `wildpc`: CLI command, module names (wildpc_core/cli/api),
  dist names, entry point `wildpc = wildpc_cli.main:main`.
- Identifiers: CastleConfig/NATSClient/DirError/MDNS -> Wildpc*.
- Env/constants: CASTLE_* -> WILDPC_*; ~/.castle -> ~/.wildpc, castle.yaml ->
  wildpc.yaml, /data/castle -> /data/wildpc.
- Systemd UNIT_PREFIX castle- -> wildpc-; own programs castle-api/gateway/etc.
- Display prose "Castle" -> "Wild PC" in docs, agent-guide files, README, frontend.
- Package dirs and bootstrap yaml renamed via git mv; lockfiles regenerated;
  redundant nested uv.lock files dropped (workspace root lock is authoritative).

Tests: core 273, cli 47, wildpc-api 120 all pass. Frontend type-checks + builds.
Fixed a stale test fixture (secret_env_path kind arg) broken pre-rename.

cli/tests/test_list.py

@@ -1,4 +1,4 @@
-"""Tests for castle list command."""
+"""Tests for wildpc list command."""
 
 from __future__ import annotations
 
@@ -7,18 +7,18 @@ from argparse import Namespace
 from pathlib import Path
 from unittest.mock import patch
 
-from castle_cli.commands.list_cmd import run_list
+from wildpc_cli.commands.list_cmd import run_list
 
 
 class TestListCommand:
     """Tests for the list command."""
 
-    def test_list_all(self, castle_root: Path, capsys: object) -> None:
+    def test_list_all(self, wildpc_root: Path, capsys: object) -> None:
         """List all components."""
-        with patch("castle_cli.commands.list_cmd.load_config") as mock_load:
-            from castle_cli.config import load_config
+        with patch("wildpc_cli.commands.list_cmd.load_config") as mock_load:
+            from wildpc_cli.config import load_config
 
-            mock_load.return_value = load_config(castle_root)
+            mock_load.return_value = load_config(wildpc_root)
             args = Namespace(kind=None, stack=None, json=False)
             result = run_list(args)
 
@@ -27,12 +27,12 @@ class TestListCommand:
         assert "test-svc" in captured.out
         assert "test-tool" in captured.out
 
-    def test_list_filter_daemon(self, castle_root: Path, capsys: object) -> None:
+    def test_list_filter_daemon(self, wildpc_root: Path, capsys: object) -> None:
         """--behavior filters the program catalog by its real behavior field."""
-        with patch("castle_cli.commands.list_cmd.load_config") as mock_load:
-            from castle_cli.config import load_config
+        with patch("wildpc_cli.commands.list_cmd.load_config") as mock_load:
+            from wildpc_cli.config import load_config
 
-            mock_load.return_value = load_config(castle_root)
+            mock_load.return_value = load_config(wildpc_root)
             args = Namespace(kind="service", stack=None, json=False)
             result = run_list(args)
 
@@ -43,12 +43,12 @@ class TestListCommand:
         # Services/jobs are deployment views, not behaviors — hidden under a filter.
         assert "test-svc" not in captured.out
 
-    def test_list_filter_tool(self, castle_root: Path, capsys: object) -> None:
+    def test_list_filter_tool(self, wildpc_root: Path, capsys: object) -> None:
         """List filtered to tools."""
-        with patch("castle_cli.commands.list_cmd.load_config") as mock_load:
-            from castle_cli.config import load_config
+        with patch("wildpc_cli.commands.list_cmd.load_config") as mock_load:
+            from wildpc_cli.config import load_config
 
-            mock_load.return_value = load_config(castle_root)
+            mock_load.return_value = load_config(wildpc_root)
             args = Namespace(kind="tool", stack=None, json=False)
             result = run_list(args)
 
@@ -57,12 +57,12 @@ class TestListCommand:
         assert "test-tool" in captured.out
         assert "test-svc" not in captured.out
 
-    def test_list_jobs_are_deployments(self, castle_root: Path, capsys: object) -> None:
+    def test_list_jobs_are_deployments(self, wildpc_root: Path, capsys: object) -> None:
         """Jobs are a deployment view: shown unfiltered, hidden under a behavior filter."""
-        with patch("castle_cli.commands.list_cmd.load_config") as mock_load:
-            from castle_cli.config import load_config
+        with patch("wildpc_cli.commands.list_cmd.load_config") as mock_load:
+            from wildpc_cli.config import load_config
 
-            mock_load.return_value = load_config(castle_root)
+            mock_load.return_value = load_config(wildpc_root)
             # Unfiltered: the job appears.
             run_list(Namespace(kind=None, stack=None, json=False))
             assert "test-job" in capsys.readouterr().out  # type: ignore[attr-defined]
@@ -73,12 +73,12 @@ class TestListCommand:
             assert "test-svc" not in out
             assert "test-tool" in out
 
-    def test_list_json(self, castle_root: Path, capsys: object) -> None:
+    def test_list_json(self, wildpc_root: Path, capsys: object) -> None:
         """JSON output tags each entry with its derived kind."""
-        with patch("castle_cli.commands.list_cmd.load_config") as mock_load:
-            from castle_cli.config import load_config
+        with patch("wildpc_cli.commands.list_cmd.load_config") as mock_load:
+            from wildpc_cli.config import load_config
 
-            mock_load.return_value = load_config(castle_root)
+            mock_load.return_value = load_config(wildpc_root)
             args = Namespace(kind=None, stack=None, json=True)
             result = run_list(args)