Make the docs state things rather than argue them

The site read as a design journal: rationale paragraphs, hedges
("deliberately", "on purpose", "genuinely"), meta-commentary about the docs
themselves, and one em-dash every ten lines carrying an aside.

Roughly twenty rationale blocks are gone or reduced to what a reader needs
in order to use the thing. Em-dashes go from 507 to 135, and what is left is
structural rather than prose: list and definition separators, table cells,
and four inside code blocks that quote what the CLI actually prints.

Also: api.example.com becomes api.fluksio.com (the emails stay, since
bootstrap.py really defaults to admin@example.com and RFC 2606 reserves it);
the mqtt table gains the two settings it had drifted behind on and inject's
wording matches the engine; llms.txt lists the two connector pages that were
in the nav but not in it; and the two device/device_policy notes now agree.

Builds clean under `zensical build --strict`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015YrQnKV3bnQd4K342y8tKj

README.md

@@ -43,7 +43,7 @@ A machine that should only *run nodes* for an engine elsewhere installs less:
 
 ```sh
 pip install fluksio-worker
-fluksio-worker --url wss://api.example.com/api/v1/workers/attach --token "$TOKEN" --labels gpu
+fluksio-worker --url wss://api.fluksio.com/api/v1/workers/attach --token "$TOKEN" --labels gpu
 ```
 
 ## Getting started