manifest: admit the logging capability for providers

[mfw78]

Problem. nullislabs/videre-nexum-module#26 (PR nullislabs/videre-nexum-module#37) admits the logging capability to the venue-adapter world, but a venue adapter declaring logging in its module.toml cannot boot: PROVIDER_CAPABILITIES is [chain, messaging] only, so CapabilityRegistry::provider().is_known("logging") is false and manifest parse fails with unknown capability "logging". Reproduced against the pinned runtime.

Scope.

• Admit logging to the provider capability set (the least-privilege case for refusing it does not apply: it grants no authority beyond emitting records the host already accepts from every module world).
• Note or fix the target-field gap: the WIT verb is log: func(level: level, message: string) and LogRecord has no target field, so "level and target intact" is structurally unreachable without an additive WIT change; decide whether to add target (additive) or document the limitation.

Dependencies. Blocks adoption of nullislabs/videre-nexum-module#26 by real adapters and nullislabs/shepherd#668.

AI Assistance: Claude Fable filed this from a red-team finding on videre PR #37 (Claude Opus red-team).

[mfw78]

Duplicate of #76, which also covers the enforcement half (an undeclared logging import is not held to the declaration). The target-field note from this issue is carried over there.