fix(formatter): restructure Tidy to match prettyhtml.com's real pipeline

.gitignore

@@ -23,3 +23,7 @@ package-lock.json
 
 # Non-Claude agent worktrees (created per CLAUDE.md isolation rules)
 .worktrees/
+
+# Raw prettyhtml.com capture — third-party copyrighted JS/CSS/HTML, local reference only.
+# Clean-room behavior specs live in planning/*.md; the raw files never get committed.
+planning/captures/

CLAUDE.md

@@ -63,7 +63,13 @@ Each tool lives in its own directory with a consistent pattern:
 
 ### Current Tools
 
-- **`/formatter/`** — HTML Formatter & Tidy. Pipeline: tokenize → indent (two-stage) → tidy → compress. Tidy dropdown is organized into three groups: **Formatting** (lowercase/sort/quote — our extras), **Cleaning (prettyhtml.com)** (the 10 options 1-for-1 with prettyhtml.com — Inline styles, Classes & IDs, Empty tags, Tags with 1 space, Successive spaces, Comments, Tag attributes, To plain text, AI Watermarks, Smart &nbsp;s; first 6 ON by default), and **Extras** (data-attrs, span-unwrap, strip-stray-line-breaks, etc.). Literal ports of `removeTagAttributes`, `aiWatermarkFixer`, and `smartNbsps` live in `formatter/app.mjs` (ES module). `normalizeStrayBreaks` (same module) runs as a pre-pass before `tidy()` to strip `<br>` residue between/around block elements and inside empty blocks (default-ON Extras option `opt-stray-breaks`), replicating prettyhtml.com's TinyMCE normalization layer without a DOM round-trip; tests in `formatter/tests/stray-breaks.test.mjs`. Tests in `formatter/tests/*.test.mjs` run via `npm test` (uses `linkedom` as DOMParser shim in Node). Options in `localStorage` key `htmlTidy_options`. See `planning/2026-05-27-prettyhtml-parity.md` for the algorithm snapshot / insurance documentation, and `planning/2026-06-24-stray-line-break-normalization-{design,plan}.md` for the stray-break feature.
+- **`/formatter/`** — HTML Formatter & Tidy. All logic lives in `formatter/app.mjs` (an ES module; there is no `app.js` here). Buttons: Indent (two-stage), Tidy, Compress.
+  - **Tidy runs through `runTidyPipeline(html, opts)`**, ordered to match prettyhtml.com's `convertText()`: stray-break normalization → whitespace pre-pass → script/style strip → to-plain-text (**first**, as theirs is) → nbsp collapse (option 5) → inter-tag gap joins → `tidy()` → nested-empty fixpoint → block-newline separation → looped whitespace post-pass → tag-attributes → AI-watermarks → smart-punctuation straightening → smart-nbsps → final cleanup. `replaceUntilStable()` mirrors their `helyettesit()` replace-to-idempotence semantics.
+  - **prettyhtml.com is two layers**: a TinyMCE DOM round-trip, then the string cleaners behind the ten checkboxes. We have no round-trip, so several default-ON **Extras** stand in for layer 1 — `opt-stray-breaks`, `opt-block-newlines`, `opt-nested-empties`, `opt-docs-residue`. Reasoning about their cleaners in isolation gives the wrong answer about what their site outputs; always check end-to-end.
+  - Dropdown groups: **Formatting** (lowercase/sort/quote), **Cleaning (prettyhtml.com)** (the 10 options 1-for-1; first 6 ON by default), **Extras** (block newlines, nested empties, Google Docs residue, script/style strip, straighten smart punctuation, stray line breaks, data-attrs, span-unwrap).
+  - **Deliberate divergences** (documented in `app.mjs` above the pipeline): E — options 1/2 parse attributes structurally rather than doing double-quote-only string surgery; G — empty-tag removal exempts `td/th/script/style/media` and requires matching tag names; H — one-space-tag removal accepts `&#160;`; N — curly quotes are accepted as attribute delimiters, which is what makes HTML pasted out of Google Docs survive.
+  - Tests in `formatter/tests/*.test.mjs` via `npm test` (`linkedom` as DOMParser shim). `parity.test.mjs` runs the pipeline against `tests/fixtures/prettyhtml-golden.json` — black-box input/output pairs captured from the live site; a fixture with an `ours` field is a recorded deliberate divergence. Options persist in `localStorage` key `htmlTidy_options`.
+  - Docs: `planning/2026-09-03-prettyhtml-complete-capture.md` is the current clean-room spec (supersedes most of `planning/2026-05-27-prettyhtml-parity.md`); `planning/2026-06-24-stray-line-break-normalization-{design,plan}.md` covers stray breaks. The raw third-party capture lives in gitignored `planning/captures/` and must never be committed.
 - **`/og-image/`** — OG Image Preview. Platform specs in `platforms.json`. Optional Cloudflare Worker CORS proxy in `functions/fetch-meta.js`. Fallback proxies for CORS.
 
 ### Suggested Tools System

README.md

@@ -70,7 +70,8 @@ Beautify, format, and clean up messy or minified HTML instantly.
 └── formatter/                  # HTML Formatter & Tidy
     ├── index.html
     ├── styles.css
-    └── app.js
+    ├── app.mjs                 # ES module — pipeline, cleaners, DOM wiring
+    └── tests/                  # node --test, linkedom DOMParser shim
 ```
 
 Each tool is self-contained in its own directory with its own `index.html`, making it easy to develop, test, and deploy independently.

eslint.config.js

@@ -41,6 +41,15 @@ module.exports = [
       },
     },
   },
+  {
+    files: ['formatter/tests/**/*.mjs'],
+    languageOptions: {
+      sourceType: 'module',
+      globals: {
+        ...globals.node,
+      },
+    },
+  },
   {
     files: ['og-image/functions/**/*.js'],
     languageOptions: {
@@ -51,6 +60,8 @@ module.exports = [
     },
   },
   {
-    ignores: ['node_modules/'],
+    // planning/captures/ holds the raw third-party prettyhtml.com capture. It is
+    // gitignored reference material, not our source — never lint or ship it.
+    ignores: ['node_modules/', 'planning/captures/'],
   },
 ];