Add Notestation Usage section

[zakoverflow]

Added instructions for accessing Notestation via Tailscale VPN by creating a .env file based on .env.example in .devcontainer/notestation/.

[Copilot]

Pull request overview

Adds documentation to help developers access the Notestation environment via Tailscale when working in the provided devcontainer setup.

Changes:

• Documented how to enable Notestation access by creating a .env file from .devcontainer/notestation/.env.example.
• Minor README reference-link formatting adjustment at the bottom of the file.

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[Copilot]

This section references creating a .env file for Tailscale, but it doesn’t explicitly call out that TS_AUTHKEY must be replaced with a valid key (per .devcontainer/notestation/.env.example) and that the auth key is sensitive. Consider adding a brief note to update TS_AUTHKEY and not share/commit the resulting .env file.

Suggested change

	To gain access to the Tailscale VPN for Notestation, create a `.env` file based on `.env.example` in the `.devcontainer/notestation/` folder. This will set up the necessary environment variables for VPN access.
	To gain access to the Tailscale VPN for Notestation, create a `.env` file based on `.env.example` in the `.devcontainer/notestation/` folder. Be sure to replace the `TS_AUTHKEY` placeholder with your valid Tailscale auth key, and treat this file as sensitive (do not share it or commit it to version control), as it contains credentials used for VPN access.

[Copilot]

README.md defines both [notehub] and [Notehub] reference links (both pointing to https://notehub.io). This duplication is unnecessary and makes link maintenance harder; consider standardizing on a single reference label and updating the uses accordingly (e.g., keep [notehub] and change [notehub.io][Notehub] to [notehub.io][notehub]).