Introduce a Resolver that owns env lookup and typed parsing for
probod-bootstrap. Env values prefixed with aws://<secret-id> are
fetched from AWS Secrets Manager (plaintext SecretString); each
secret ID is cached per run. Builder now takes a Resolver only.
Prefix every probod-bootstrap input with PROBOD_ so bootstrap config
does not collide with unrelated process environment (for example
AWS_* used by other tooling). Secrets Manager authentication uses
the standard AWS SDK default chain (AWS_REGION, IAM role, profile);
PROBOD_AWS_* vars configure S3 in the generated config only.
Update Helm deployment env names, GNUmakefile dev-config, Lima
provision, e2e testutil, compose.prod.yaml, and docs.
Deployments must rename bootstrap env vars to PROBOD_* (e.g.
AUTH_COOKIE_SECRET → PROBOD_AUTH_COOKIE_SECRET).
BREAKING CHANGE: all env vars are now prefixed by `PROBOD_`.
Signed-off-by: Ludovic Vielle <ludovic@probo.com>
