feat(noctalia): add knowledge lookup panel

Provide a portable, cache-ignored Obsidian vault lookup plugin and bind it to Super+N.

.local/share/noctalia/plugins/knowledge-lookup/create-entry.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+"""Safely create one direct child in the configured knowledge vault."""
+
+from __future__ import annotations
+
+import json
+import sys
+from pathlib import Path
+
+
+def fail(message: str) -> int:
+    print(message, file=sys.stderr)
+    return 1
+
+
+def child_name(raw: str) -> str | None:
+    name = raw.strip()
+    if not name or name in {".", ".."} or "/" in name or "\\" in name or "\0" in name:
+        return None
+    if name.startswith("."):
+        return None
+    return name
+
+
+def main() -> int:
+    if len(sys.argv) != 5:
+        return fail("usage: create-entry.py VAULT KIND CURRENT_DIRECTORY NAME")
+    raw_vault, kind, current_directory, raw_name = sys.argv[1:]
+    vault = Path(raw_vault).expanduser().resolve()
+    if not vault.is_dir():
+        return fail(f"vault does not exist: {vault}")
+    if kind not in {"note", "directory"}:
+        return fail("kind must be note or directory")
+    current = (vault / current_directory).resolve()
+    if current != vault and vault not in current.parents:
+        return fail("current directory escaped the vault")
+    if not current.is_dir():
+        return fail("current directory no longer exists")
+
+    name = child_name(raw_name)
+    if name is None:
+        return fail("use a non-hidden direct name without slashes")
+    if kind == "note" and not name.lower().endswith(".md"):
+        name += ".md"
+    target = (current / name).resolve()
+    if target.parent != current:
+        return fail("target escaped the current directory")
+
+    try:
+        if kind == "directory":
+            target.mkdir()
+        else:
+            title = target.stem
+            with target.open("x", encoding="utf-8") as handle:
+                handle.write(f"# {title}\n")
+    except FileExistsError:
+        return fail(f"already exists: {name}")
+    except OSError as error:
+        return fail(f"cannot create {name}: {error}")
+
+    relative = target.relative_to(vault).as_posix()
+    json.dump(
+        {
+            "kind": kind,
+            "relative": relative,
+            "name": name,
+            "absolute": str(target),
+        },
+        sys.stdout,
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())