fix(docs): validate ActionSpec claim counts

[TayfurYldz]

Closes #450

Problem

Lines mentioning ActionSpec were exempted from action-count validation entirely, so stale subset counts could pass the public-claims checker. The developer guide had consequently drifted from 189 to the generated table's 191 entries.

Fix

• derive the ActionSpec count from generated rows in docs/action-reference.md
• fail closed if that generated table yields no rows
• validate qualified ActionSpec counts instead of skipping them
• correct the developer-guide executor count to 191
• add regression coverage for a stale count, exact row derivation, and the empty-table failure

Validation

• python3 scripts/check_evidence_claims.py .
• bash tests/release/public-claims.test.sh
• git diff --check
• attempted cargo nextest run --workspace --locked; it could not complete on this WSL host because the system glib-2.0 development package is unavailable to pkg-config (glib-2.0.pc missing). No Rust files are changed by this PR.