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-# Plan — second demo (#42) and About sidebar (#43)
-
-## Stack (each PR targets the branch below it)
-
-| Issue | Branch | Base |
-|-------|--------|------|
-| #42 | `feat/demo-text` | `main` |
-| #43 | `feat/about-sidebar` | `feat/demo-text` |
-
-Merge from the bottom up.
-
-## #42 — second demo: one long text
-
-Decisions:
-
-- Source: Project Gutenberg #3420, `https://www.gutenberg.org/cache/epub/3420/pg3420.txt`.
-  The script pins the SHA-256. A mismatch stops the build. The maintainer then reviews the new
-  file and updates the hash. No mirror: the pinned hash already detects a change in place.
-- `scripts/build_demo_text.py` writes `simple_topic_modeling/data/demo_text.txt` and
-  `scripts/demo_text.provenance.json`. It removes the Gutenberg header, footer, and licence.
-  It joins each hard-wrapped paragraph into one line and keeps a blank line between paragraphs.
-- `io.demo_text()` reads the file with `importlib.resources`.
-- The source radio gets two demo options: **Demo: newspapers** and **Demo: book**.
-- Two buttons above Step 1: **Run demo** (newspapers) and **Run book demo**.
-- The book demo opens in **Ordered text** mode, split on blank lines, in English.
-- The language controls join the `touched` map, so a change of source keeps the reader's values.
-- The start topic count for the book comes from a measured test. The comment in `app.py`
-  holds the reason.
-- Update `NOTICE`, the About section, the language help, and `SPECS.md`.
-
-## #43 — About in the sidebar
-
-- Move **Run**, the summary, and **Run model** to the start of Step 3. Keep `run_button`.
-- Put the About text in `mo.sidebar`. Remove the About cell at the end of the page.
-- Update `SPECS.md` Step 3 and the About rule.
-
-## Checks for each PR
-
-- The section 4 gate, `marimo check`, and the `app.run()` check.
-- Every cell parameter is some cell's return value.
-- Browser: Run model, Run demo, Run book demo, and Rerun each start one fit, in `marimo edit`
-  and in the exported `dist/`.
-- #43: the sidebar at phone width.
-
-## Status
-
-- [x] #42 build script
-- [x] #42 package and app
-- [x] #42 checks (gate, app.run, marimo edit + dist browser runs)
-- [x] #43 app and specs
-- [x] #43 checks (gate, app.run, marimo run + dist browser runs, 500 px drawer)
-
-## Open after the merge
-
-- Delete `PLAN.md` when both PRs are merged.