Complete SliM V0.5 conformance coverage

[killertux]

The final SliM V0.5 gaps were in FitNesse-facing conversions, error rendering, Temoc's recursive result state, and process-level compatibility coverage. This change adds the optional HTML hash converter and bracketed collection conversion, preserves null/list/object values through symbol and fixture chaining, emits standard errors in FitNesse's message:<<...>> envelope, and returns NO_INSTANCE before fallback dispatch for missing targets.

It also migrates Temoc's client-side symbol state to recursive values, hardens port selection and failed child startup, uses the shared TCP/port-1 runner in the calculator example, and adds real child-process tests over TCP and stdin/stdout. The tests cover Unicode, nested lists, all instructions, constructors and failures, symbol types, SUT/library/actor behavior, control flow, repeated batches, exact output tunneling, and HTML hashes. CI now runs workspace tests with all features and Clippy across all targets/features.

The conformance matrix documents two runtime limits: timeouts are observed after in-process fixture calls return, and stdio output tagging uses the explicit OutputTunnel adapter. A live external FitNesse suite is not yet part of CI.

Validation:

• cargo test --workspace --all-features
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo fmt --all -- --check
• Independent protocol review with no remaining blockers