chore: release v0.1.1 — require Steg ^1.0.1

[ndrstmr]

Summary

• Bumps the ndrstmr/steg constraint from ^1.0 to ^1.0.1.
• The bundle's InferenceClientInterface::class DI alias points at a StegClient instance. StegClient only formally implements the interface as of Steg v1.0.1 (see fix: StegClient implements InferenceClientInterface steg#1).
• Installing this bundle against Steg v1.0.0 triggered a TypeError at request time whenever a consumer typehinted InferenceClientInterface in their constructor.
• Adds CHANGELOG entry and a README note about the minimum Steg version.

Test plan

• composer validate --strict
• PHPStan level 9 — no errors
• PHPUnit — 28 tests, 66 assertions green
• PHP-CS-Fixer — clean
• Local PoC consumer (apps/ls-agent in lotse-workspace) renders HTTP 200 against the updated stack
• After merge: tag v0.1.1 on the merge commit so Packagist picks it up