fix: normalize proof linkage keys for canonical finding mapping

[davidahmann]

Problem

A PR #72 review identified that related_record_ids linkage could be missed when risk canonical keys and finding canonical keys differed in org normalization (for example, empty/whitespace org inputs).

Changes

• Normalized canonical lookup keys in proof emission linkage logic before map lookups.
• Indexed finding record IDs by both original and normalized canonical forms.
• Added regression coverage for empty-org finding input to assert risk record linkage is preserved.
• Included existing product/dev_guides.md update from current workspace as requested.
• Reviewed PR build(deps-dev): bump minimatch from 3.1.2 to 3.1.5 in /docs-site in the npm_and_yarn group across 1 directory #73 (Dependabot minimatch lockfile bump), validated green checks, and merged it before this fix.

Validation

• make prepush-full
• go test ./core/proofemit/... ./core/proofmap/... -count=1