feat: add composable artifact forest profiles

[szmyty]

Closes #363

Summary

• add the versioned renderflow.profile/v1 model with deterministic inheritance/composition
• add required/optional target roles, per-target options, and format/family/capability/provider/role/transform/variant selectors
• ship the data-defined bundled everything profile
• expand maximal forests from detected source capabilities while keeping network and AI policy-gated
• prune unavailable optional/maximal branches locally and record selected, excluded, unavailable, and budget-pruned decisions
• attach requested profile versions, resolved branches, target configuration, and produced artifact ids to plan/run evidence
• add build --profile ... --exclude kind:value and graph plan --profile ... --exclude kind:value
• update v2/run schemas and user documentation

Verification

• cargo check --workspace --all-targets
• renderflow graph plan --profile everything --exclude family:video --format json
• renderflow build --profile everything --exclude family:video --dry-run
• git diff --check

Broad test/CI expansion is intentionally deferred per the current sprint convention.