CLI auth pairing create writes tokens to wrong DB subdirectory (userdata vs dev) #112

Problem

t3 auth pairing create writes the pairing token to a subdirectory of the server's persistent state. The subdirectory depends on whether --dev-url is passed:

• Without --dev-url: writes to userdata/ subdirectory
• With --dev-url: writes to dev/ subdirectory

The dev server started with --dev-url http://localhost:5734 reads tokens from the dev/ subdirectory. If the token was minted without --dev-url, it was written to userdata/ and the dev server never sees it.

Impact

# This writes to userdata/ — token will be silently invalid against the dev server
node apps/server/src/bin.ts auth pairing create --base-dir ~/.t3-hcode

# This works correctly (writes to dev/)
node apps/server/src/bin.ts auth pairing create \
  --base-dir ~/.t3-hcode --dev-url http://localhost:5734

The pairing URL appears to work — the user pastes it into the browser, the pair page loads — but the token is never recognized by the server. No error or warning explains the mismatch.

Fix

At minimum, the CLI should print a warning when --dev-url is absent but the configured server uses one (or vice versa). Ideally, deriveServerPaths (apps/server/src/cli/config.ts:282) should surface the subdirectory choice in the pairing token output so the user can verify alignment.