Handle unknown claw-api principal verbs without crash-looping

[mostlydev]

Summary

• make claw-api tolerate forward-unknown principal verbs at runtime instead of failing startup
• filter unrecognized verbs out of the loaded principal store and emit warnings on service startup
• keep strict compiler-side validation intact and add regression coverage for tolerant runtime loading

Testing

• go test ./internal/clawapi ./cmd/claw-api
• go test ./...

Notes

This addresses the outage-class runtime behavior from #120. It does not yet add a separate claw up compatibility warning for skew against an older deployed claw-api image.

[mostlydev]

Addressed the structural review follow-up in 13d0530.

Changes made:

• removed the dead strict verb-validation path from internal/clawapi/principal.go
• kept structural validation fail-closed, but made LoadStore's tolerant verb-filtering contract explicit in tests
• updated regression coverage so public LoadStore behavior is what the tests assert
• filed Warn on claw-api principal verb skew and surface inert principals #144 for the remaining non-runtime scope from claw-api crash-loops on unknown principal verbs instead of warning #120: deploy-time skew warnings and operator-visible surfacing for inert principals

Verification:

• go test ./internal/clawapi ./cmd/claw-api
• go test ./...