skillscript-runtime v0.9.5

Two mechanical lint fixes from Perry's R-series next-ring (77ed6c65).
Standalone patch ahead of the AgentConnector audit work — keeps
contract-design surface separate from cold-author polish per the
thematic-discipline pattern that worked through v0.9.x. No contract
surface touched; v1.0 cold-author signoff (mean UX 4.0/5 against
v0.9.4) still stands as the gate-1 baseline.

Fixed — fallback-trailer lint-layering

Cold authors expected (fallback: ...) on a bare $ TOOL op to
suppress the tier-1 unwired-primary-connector error (the intuition:
"if I provide a fallback, the runtime is guarded"). It didn't — lint
runs at authoring-time and fallback resolves at dispatch-time, so the
error fired regardless of fallback presence. The layering wasn't
obvious from the diagnostic.

Fix: when every call site for a (target, tool) pair carries an
op-level (fallback: ...) trailer, demote the finding from error
to info. The advisory message explains the layering ("Lint runs at
authoring-time and the fallback resolves at dispatch-time; the
runtime branch is reached only if dispatch fails in production"). If
any call site lacks a fallback, the error stays. Per R8 cold-author
finding in 77ed6c65.

Fixed — forward-reference noise dedup

Pre-v0.9.5 lint emitted up to 4 diagnostics for 2 missing skills:
unknown-skill-reference keyed by via:name (so the same missing
skill referenced via both & and $ execute_skill produced 2
findings) AND the paired deferred-skill-reference advisory doubled
the count. Per Perry's "4 diagnostics for 2 missing skills" cold-author
finding — noisy without adding signal.

Fix:

• unknown-skill-reference now dedups by skill name (not via:name);
  the message lists all vias encountered.
• deferred-skill-reference advisory removed entirely — the warning's
  remediation field already explains the forward-ref path. One warning
  per missing skill carries the same signal.

Net: 2 missing skills × dual-ref produces 2 findings (down from 8).
Cold author noise floor reduced; pre-adoption rule applies (no
external migration needed).