feat: add Obsidian CLI API service

- Add Docker image for the official Obsidian desktop app and CLI.

- Start Obsidian headlessly with Xvfb and DBus setup.

- Expose a safe structured HTTP command API without shell execution.

- Add JWT-based vault, path, and command authorization.

- Support single-vault and multi-vault container mounts.

- Add TypeScript SDK helpers for Obsidian CLI commands.

- Add n8n community node package with Obsidian operations.

- Add docs, compose config, tests, and production image workflow.

.env.example

@@ -0,0 +1,34 @@
+# Copy to .env and adjust.
+
+# JWT signing secret. Use the same value to create JWTs with scripts/create_jwt.py.
+OBSIDIAN_JWT_SECRET=change-this-long-random-secret
+
+# Host path to your default/single Obsidian vault.
+# Examples:
+# OBSIDIAN_VAULT_PATH=/home/daniel/Documents/Obsidian/MainVault
+# OBSIDIAN_VAULT_PATH=/mnt/storage/ObsidianVault
+OBSIDIAN_VAULT_PATH=./vault
+
+# Optional: mount a parent folder containing additional vaults at /vaults.
+# Then register all vaults by name using container paths.
+# Example:
+# OBSIDIAN_VAULTS_ROOT=/home/daniel/Documents/Obsidian
+# OBSIDIAN_VAULTS=main=/vault,work=/vaults/Work,personal=/vaults/Personal
+OBSIDIAN_VAULTS_ROOT=./vaults
+OBSIDIAN_VAULTS=
+
+# Host port for the HTTP API.
+OBSIDIAN_API_PORT=8080
+
+# Official Obsidian desktop/CLI version installed in the image.
+OBSIDIAN_VERSION=1.12.7
+
+# Official CLI binary inside the container.
+OBSIDIAN_CLI_BIN=obsidian
+
+# Seconds to wait for the desktop app to expose the official CLI socket.
+OBSIDIAN_STARTUP_TIMEOUT=60
+
+# Command timeout limits in seconds.
+COMMAND_TIMEOUT=60
+MAX_COMMAND_TIMEOUT=300