Rename clicktrack.js — a content blocker was eating it and killing the app

A file called `clicktrack.js` matches the click-tracking telemetry patterns that
EasyPrivacy and similar lists block by substring. In a browser with a content
blocker the request never completes, and because it is a module import that
takes the entire graph with it: main.js never runs, no handler is ever bound,
and every control in the UI sits there looking correct and doing nothing.

The failure is unusually expensive to diagnose because everything else looks
healthy. The dev server returns 200 with the right MIME type, curl fetches it
fine, node imports it fine, and the app loads perfectly in any browser without a
blocker — which is how it passed every check here. Only the console names it,
and only as one line about a module that failed to load.

Renamed to metronome.js, which is also the better name for what it does. The
button id went with it, since cosmetic filter rules can hit ids too.

The general rule, recorded at the top of the file: anything shipped to a browser
and named like tracking will be treated as tracking. Avoid click, track,
analytics, pixel, beacon and ad in filenames and URL paths, however honest the
code behind them is.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

flow-state/src/audio/metronome.js

@@ -1,6 +1,17 @@
-// Click track — the Phase 1 gate, and the most useful validation tool in the
+// The metronome — the Phase 1 gate, and the most useful validation tool in the
 // project.
 //
+// NAMED CAREFULLY. This file was `clicktrack.js` until a content blocker ate it:
+// `clicktrack` is a click-tracking telemetry pattern that EasyPrivacy and
+// friends block by substring, so the request died in the browser, the module
+// graph died with it, main.js never ran, and every control in the app went
+// inert while looking perfectly fine. The server was serving it with a 200 the
+// whole time.
+//
+// Anything shipped to a browser and named like tracking will be treated as
+// tracking. Avoid `click`, `track`, `analytics`, `pixel`, `beacon` and `ad` in
+// filenames and URL paths, however honest the code behind them is.
+//
 // Beat detection cannot be judged by watching visuals: a grid that is 20ms late
 // or at half tempo still "looks kind of right". Mixing an audible click onto the
 // detected grid makes the answer immediate and unambiguous. Downbeats get a

flow-state/src/audio/tempo.js

@@ -4,7 +4,7 @@
 // a causal detector has to converge, and lags for the first several bars of every
 // section. Here the grid is exact from frame zero, and phase is fitted globally.
 //
-// The click track (audio/clicktrack.js) exists to validate this by ear. If the
+// The metronome (audio/metronome.js) exists to validate this by ear. If the
 // clicks don't sit on the beat, nothing downstream can be trusted — every timing
 // artefact in the finished video traces back to this file.
 

flow-state/src/main.js

@@ -5,7 +5,7 @@ import { formatTime } from './audio/decode.js';
 import { describeLook } from './look/LookGenerator.js';
 import { toHex } from './look/palette.js';
 import { applyGrainToPost, describeGrain, GRAIN_MASKS, GRAIN_MODES } from './look/grain.js';
-import { renderClickTrack, audioBufferToWavBlob } from './audio/clicktrack.js';
+import { renderClickTrack, audioBufferToWavBlob } from './audio/metronome.js';
 import { Exporter, exportSegment, downloadBlob, PRESETS, isSupported } from './export/Exporter.js';
 
 const QUALITY = {
@@ -328,10 +328,10 @@ function renderPanel() {
                         ${s.shots ? `<i class="dim">${s.shots.length} shots</i>` : ''}</span>
                     <b>${(s.variants || [s.layers]).map((v) => v[0].module.name).join(' / ')}</b>
                 </div>`).join('')}
-            <button id="btn-clicktrack" class="wide">download click track</button>
+            <button id="btn-metronome" class="wide">download click track</button>
             <div class="hint">Mixes clicks onto the detected beat grid. If they don't sit on
             the beat, tempo detection is wrong and everything downstream inherits it.</div>`;
-        document.getElementById('btn-clicktrack').addEventListener('click', downloadClickTrack);
+        document.getElementById('btn-metronome').addEventListener('click', downloadClickTrack);
         return;
     }
 
@@ -562,11 +562,11 @@ document.getElementById('btn-segment').addEventListener('click', () => runExport
 
 async function downloadClickTrack() {
     if (!state.show.ready) return;
-    const button = document.getElementById('btn-clicktrack');
+    const button = document.getElementById('btn-metronome');
     button.textContent = 'rendering…';
     try {
         const buffer = await renderClickTrack(state.show.audioBuffer, state.show.track.tempo);
-        downloadBlob(audioBufferToWavBlob(buffer), `${state.show.fileName}-clicktrack.wav`);
+        downloadBlob(audioBufferToWavBlob(buffer), `${state.show.fileName}-metronome.wav`);
         button.textContent = 'download click track';
     } catch (err) {
         button.textContent = `failed: ${err.message}`;
@@ -652,3 +652,9 @@ if (import.meta.env && import.meta.env.DEV) {
 
 requestAnimationFrame(frame);
 resize();
+
+// Tell the boot guard in index.html that the module graph made it all the way
+// through. Without this the guard cannot distinguish "still starting" from
+// "never going to start", and the failure it exists to catch is exactly the one
+// that produces no error at all in the page.
+window.__FLOW_STATE_READY__ = true;