Refresh Vault token from disk on each Consult.load call

[nogazr]

The Vault Ruby gem caches the token in memory at client initialization and never re-reads. The token is being renewed and written to a shared volume (symlinked to ~/.vault-token), but the running Rails process keeps using the stale cached token. This causes 403 "invalid token" errors when templates are re-rendered at runtime.

Adding c.token = Vault::Defaults.token to configure_vault forces the client to re-read the token from ~/.vault-token on every Consult.load call, picking up vault-agent's renewed token.

Test Plan

1. Start a console session

bin/console

2. Load config and remove the explicit token

Consult.load config_dir: 'spec/support'
Consult.config[:vault].delete(:token)

This simulates a production consult.yml key, relying on a local token agent instead.

3. Write a first token to disk

echo 'first-token' > ~/.vault-token

4. Call configure_vault and verify

Consult.configure_vault
Vault.client.token # => "first-token"

5. Simulate a token rotation

In a separate terminal:

echo 'second-token' > ~/.vault-token

6. Call configure_vault again and confirm the new token is picked up

Consult.configure_vault
Vault.client.token # => "second-token"

7. Restore your real Vault token when done

vcli init --force