Start av-club: what it is, and a verified installer

Media processing pulled out of the website that first needed it. ffmpeg,
ImageMagick, libvips and exiftool are a real installation rather than an npm
install, and encoder settings get revisited as browser support moves — neither of
which belongs on the same clock as page templates and database schemas.

No processing code yet. What is here is the tooling requirement, an installer, and
docs/PIPELINE.md writing down what has NOT been decided — how a consumer talks to
this, whether processing blocks an upload, where output goes — so those get chosen
deliberately instead of by whatever gets written first.

verify.sh checks by running: it encodes a video and probes the result against what
ffmpeg was told to make, loads sharp under Bun specifically, and asserts a
re-encode still strips GPS. That last one guards a real leak — if a future sharp
changes its default, this fails a check rather than quietly publishing the
coordinates of a client's living room. Confirmed non-vacuous by hiding ffmpeg and
watching it exit 1.

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

tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "lib": ["ESNext"],
+    "target": "ESNext",
+    "module": "Preserve",
+    "moduleDetection": "force",
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "noEmit": true,
+
+    "strict": true,
+    "skipLibCheck": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedIndexedAccess": true,
+    "noImplicitOverride": true
+  }
+}