Fix Round 3 sweep, parsing, logging, and validation regressions

Normalize sweep metric vector validation behavior

Fix round-2 schematic/meas/queue regressions and add coverage

Harden LTspice MCP input validation and loader state handling

Harden MCP validation, sweep/verification semantics, and provenance safety

chore: ignore local docs image export directory

fix: harden run artifacts, queue snapshots, and sweep/meas parsing

docs: use bridge rectifier schematic as primary example

docs: improve onboarding and GitHub discoverability

Ignore .mcp-workdir runtime artifacts

Fix queue worker crash and harden timeout/meas handling

Update docs, smoke coverage, and parser/test ergonomics

Fix ascii CLI order and reject stale LTspice artifacts

Fix LTspice measurement parity for stepped logs and settling metrics

Fix transient time axis + meas AT parsing for metric parity