Document Email Security and Code Security GA pricing and trials

[maximelb]

Email Security and Code Security are generally available. These docs describe extension subscription as the purchase, daily protected-mailbox/repository pricing, and the existing free-tier trial model.

• Email Security: $1 per protected mailbox per month, billed daily at $1/30 per mailbox-day.
• Code Security: $0.80 per protected repository per month, billed daily at $0.80/30 per repository-day, plus the existing Cloud Security base fee.
• Free tier: sensor quota of 2 or less; 14-day trials. Email Security covers 25 mailboxes per organization. Code Security allows 2 provider connections, 10 repositories per connection, and 5 container images per organization for hosted scanning.
• Expiry pauses collection/scanning and keeps configuration. Trial-expiry purge grace is 30 days for email and 7 days for code, starting when expiry is observed. Raising sensor quota above 2 lifts trial limits and starts usage billing.

Adds a Billing → Security Products page, removes private-beta availability language throughout Email Security, and updates the email setup/policy and code setup/overview pages. No activation, quote, or purchase-consent workflow is documented. Provider permission grants and response-action confirmations retain their separate meanings.

Corrects the existing organization-deletion row to its implemented 7-day grace period, removes unsupported promises about post-expiry remediation and exact recovery timing, and explains that the existing CLI examples require command groups not yet present in the stable CLI package.

Validation: strict MkDocs build passed; ordered-list numbering and release-note headings have no new issues; all nine release feeds passed. Rates, trial limits, and grace periods were checked against implementation. Self-review checked public-only content, navigation, cross-references, trial upgrade/cancellation semantics, and daily-rate arithmetic.

Supersedes #487. Leave unmerged for the orchestrator.

[maximelb]

/lc-review

[maximelb]

Self-review complete on ade51a0: no open findings.

Checked subscription-as-purchase wording, daily protected-population rates and the 30-day divisor, the separate Cloud Security base fee, trial eligibility and limits, configuration preservation at expiry, upgrade cancellation of trial-expiry purge, and asynchronous deletion after the observed-expiry grace period. Checked that all added content uses public product/API names and public links, and that provider consent and response-action confirmation are not confused with a purchase flow.

Strict MkDocs build passed on this commit. All CI checks on the current commit are green: rendered docs, internal links, Markdown, Python unit tests, Go snippets, and Python snippets. Ordered-list numbering and release-note headings had no new issues, and all nine release feeds passed. The existing CLI examples are explicitly qualified because their command groups are absent from the current stable package.

#487 is closed as superseded. Leave this PR unmerged for the orchestrator. /lc-review was requested. A lcbill approval is recorded on the current commit with an empty review body; no substantive review findings were returned.