docs: name bot-bottle, not ./cli.py, in every instruction

`doctor` told users to run `./cli.py backend setup`. cli.py is a four-line
wrapper at the repo root that calls bot_bottle.cli:main, and it does not ship —
[tool.setuptools.packages.find] includes only bot_bottle*, so anyone who
installed rather than cloned has no such file. Confirmed against a real
install: the user's tree contains exactly one executable, `bot-bottle`, and no
cli.py anywhere, while doctor recommended `./cli.py` three times. Invisible in
development, where ./cli.py works fine from a checkout, which is why only a
clean-install test surfaced it.

The two entry points are the same code, so the fix is to name the one that
always exists. 141 replacements across 45 files: the runtime messages that
caused this, plus README, docs, PRDs, research notes and test prose, so nothing
teaches the invocation a user cannot run.

scripts/demo.sh is deliberately untouched — it *executes* ./cli.py from a
checkout, where that is the correct and available path.

Verified end to end: a sandbox install now reports
"Run: bot-bottle backend setup --backend=firecracker", and bot-bottle is on
that user's PATH. Unit suite unchanged against the pre-existing baseline.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WEfZZhakx13bxTfXcZCoS5

docs/prds/0021-dashboard-tmux-split-pane.md

@@ -46,7 +46,7 @@ window, two panes, no terminal handoff.
 
 ## Goals / Success Criteria
 
-1. When the operator runs `./cli.py dashboard` from inside a
+1. When the operator runs `bot-bottle dashboard` from inside a
    tmux session (`$TMUX` set), the dashboard establishes a
    two-pane layout: dashboard in the left pane, an initially-
    empty right pane reserved for claude sessions.
@@ -313,7 +313,7 @@ Sized small.
 3. **Dashboard launched OUTSIDE tmux but tmux is installed.**
    Should the dashboard auto-exec itself inside a fresh tmux
    session to get the split-pane experience? Convenient but
-   surprising (`./cli.py dashboard` shouldn't silently
+   surprising (`bot-bottle dashboard` shouldn't silently
    change what session you're in). v1 leaves this off —
    operators who want split-pane mode start tmux themselves
    and then run the dashboard.
@@ -332,7 +332,7 @@ Sized small.
    PRD-0019 focus indicator?
 
 6. **Concurrent dashboards in different tmux windows.**
-   Multiple `./cli.py dashboard` invocations in different
+   Multiple `bot-bottle dashboard` invocations in different
    tmux windows would each create their own right pane —
    probably fine, each has its own state, but worth
    verifying that `tmux list-panes` is scoped to the right