feat: add warning for Pi extension installation in rooms and document…

[steffenboe]

… pi extension boundary more clearly

closes #3

[ferpastoralonso]

Merged, and an apology first: this sat for well over a week before our review process caught up with it, which is on us, not you. The gap you identified was real on both halves, and we took both: the docs section and the install-time hint. Landing it, we made three adjustments on our side: the note fires only on an actual install (it also printed on install --help and bare install), the wording moved to our product voice, and we corrected one thing you could not have known: skills bundled inside installed packages do not reach rooms either, they only arrive through the skill library in the web app, so the docs paragraph now tells that fuller story. Process notes: we land through our mainline and mirror here, so this PR shows closed rather than merged, with your authorship preserved and changelog credit in the next release. And the DCO sign-off requirement in CONTRIBUTING postdates your PR, so it does not apply to it; future contributions will want git commit -s. Thanks for being the first to file an issue and ship the fix for it in the same breath.