Improve self-awareness

Today a room does not know which version of exxperts it runs in. It also cannot read the documentation that came with the installation. The agent instructions send the room to the documentation on GitHub `main`. That documentation can be newer than the installed application.

I'd love a room to know two things without a web request:

1. the installed version
2. the capability documentation of that version

This is good in these cases:

- A user asks what exxperts can do for them. The room answers for the installed version. It does not answer for a newer version with different features.
- A user asks how a feature works. The room gives the correct name of the control in the interface. It does not give a name from a different version.
- A room has no web access, or the network is not available. The room can still explain the product.
- A user asks what is new after an update. The room can read the changelog of the installed version.
- A room helps a new user to start. Correct guidance makes the room a good introduction to the product.

pi does this well. It puts its documentation and its examples into the installed package. Then pi writes the absolute paths of these files into the system prompt, together with a short table that shows which file answers which type of question. The agent reads a file only when a user asks about pi. pi also reads its version at run time from the installed package, and it shows the changelog entries after an update. As a result the documentation that the agent reads is always the documentation of the version that runs.

Exxperts already ships the necessary files. The package contains `docs/` and `CHANGELOG.md`. Maybe (?) only the connection between the room and these local files is missing.

Goals:

1. A room knows the installed version of exxperts.
2. A room can read the documentation that came with the installation.
3. A room can read the changelog of the installed version.
4. A room finds the correct document for a question quickly. It does not read all documents.
5. A room uses the local documentation first. It uses the documentation on GitHub only to compare the installed version with a newer version.
6. A room uses the same words as the user interface, especially for the memory functions. If the internal name and the name in the interface are different, the room gives the name that the user can see.
7. A room does these things in every mode. A room without shell access and without a workspace also knows its version.

Start by inspecting the shipped docs/ directory and CHANGELOG.md, then trace how a room builds its agent instructions and obtains the installed version in each mode. Define how local documentation paths, version information, changelog access, and targeted document selection reach the room without a web request; done means every mode uses documentation matching the installed version and can answer update questions.

Written by the indexing model from the issue text.