fix(platform): redact spaced secret assignments

[XnLemon]

Objective

Close another Phase2 sensitive-output gap by redacting common secret assignments that include spaces around = or : separators.

Changes

• Extended default platform redaction patterns for api_key, token, secret, password, passwd, and cookie assignments with optional whitespace around separators.
• Preserved compatibility with existing no-space key=value and key:value forms.
• Added regression coverage for spaced api_key, password, token, secret, and cookie values.

Validation

• go test ./platform
• go vet ./platform
• git diff --check
• open-code-review subagent/manual review: 0 High / 0 Medium / 0 Low

Risks / Follow-up

• This increment only broadens platform redaction for spaced secret assignments; remaining Phase2 closure items will continue in follow-up fork-only PRs.