fix(qa): correct rootDir comment that opens "No rootDir" above one that sets it (#11919)

git history (full clone): the file was created (#3349) with `"rootDir": "."`
and no comment. The very same commit that later broadened it to
`"rootDir": "../../.."` (#7526/#7584) also introduced the seven-line comment
whose opening sentence claims there is none — the contradiction was there from
the moment the comment was written, not a later drift. `git log -S'rootDir'`
on this path finds only those two commits; no earlier form of the file ever
had a bare "no rootDir" state, so disposition is a one-sentence wording fix,
not a removal.

Verified the comment's own argument still holds: the only file in the package
importing outside it (route-ledger-live-mount-parity.dogfood.test.ts) resolves
all five of its relative imports under `../../..`, so the declared rootDir
still never constrains anything. `tsc --showConfig` is byte-identical
before/after (comments are stripped before parsing) — no behaviour change.

Scope: this one file's comment text only, per #10899's standing fence.

Fixes #11476

Claude-Session: https://claude.ai/code/session_015ahemw8RcTgqtxrj15PEZx

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-steve

packages/qa/dogfood/tsconfig.json

@@ -8,13 +8,14 @@
     "skipLibCheck": true,
     "noEmit": true,
     "types": ["node"],
-    // No `rootDir`. This project emits nothing (`noEmit`), so `rootDir` never
-    // shaped an output layout here — its only effect was to forbid importing a
-    // sibling package's SOURCE file, and the route-ledger ↔ live-mount parity
-    // gate (#7526) must read the five ledgers exactly that way: each one is
-    // package-internal on purpose (the guard's data, not public API), so there
-    // is no entry point to import them from. Every other ledger guard in the
-    // repo compiles them as relative sources for the same reason.
+    // `rootDir` is set to the repo root — wide enough to be a no-op. This
+    // project emits nothing (`noEmit`), so `rootDir` never shaped an output
+    // layout here — its only effect was to forbid importing a sibling
+    // package's SOURCE file, and the route-ledger ↔ live-mount parity gate
+    // (#7526) must read the five ledgers exactly that way: each one is
+    // package-internal on purpose (the guard's data, not public API), so
+    // there is no entry point to import them from. Every other ledger guard
+    // in the repo compiles them as relative sources for the same reason.
     "rootDir": "../../.."
   },
   "include": ["test/**/*"],