docs(tw_section): update stale typed-wasm proposal 0001 reference (accepted + ADR-0002/0003)

[hyperpolymath]

Summary

`lib/tw_section.mli` describes the forward-compatibility slot for
typed-wasm carrier-section encoders. Its header gates that slot on
"the proposal promotes to [accepted]" — but the gating event
happened on 2026-05-30:

• typed-wasm proposal 0001 (`docs/proposals/0001-multi-producer-carrier-section.adoc`) reached `[accepted]` and was promoted to typed-wasm ADR-0002 in typed-wasm#116
• typed-wasm proposal 0002 (`docs/proposals/0002-access-site-carrier.adoc`) reached `[accepted]` and was promoted to typed-wasm ADR-0003 in the same PR

This PR refreshes the header to reflect the new state and adds
`access_sites` to the list of encoders the slot reserves, with a
pointer to active downstream work (#462). No substantive behaviour
change — encoders still land here as codegen produces them.

Test plan

• CI green (single-file .mli comment update)

🤖 Generated with Claude Code

[github-actions]

🔍 Hypatia Security Scan

Findings: 83 issues detected

Severity	Count
🔴 Critical	2
🟠 High	13
🟡 Medium	68

⚠️ Action Required: Critical security issues found!

View findings

[
  {
    "reason": "Action perpolymath/standards/.github/workflows/governance-reusable.yml@main\n needs attention",
    "type": "unpinned_action",
    "file": "governance.yml",
    "action": "pin_sha",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Action ons/checkout@v6\n    needs attention",
    "type": "unpinned_action",
    "file": "publish-jsr.yml",
    "action": "pin_sha",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Action land/setup-deno@v2\n    needs attention",
    "type": "unpinned_action",
    "file": "publish-jsr.yml",
    "action": "pin_sha",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in affine-vscode-publish.yml",
    "type": "missing_timeout_minutes",
    "file": "affine-vscode-publish.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in casket-pages.yml",
    "type": "missing_timeout_minutes",
    "file": "casket-pages.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in casket-pages.yml",
    "type": "missing_timeout_minutes",
    "file": "casket-pages.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in ci.yml",
    "type": "missing_timeout_minutes",
    "file": "ci.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in ci.yml",
    "type": "missing_timeout_minutes",
    "file": "ci.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in ci.yml",
    "type": "missing_timeout_minutes",
    "file": "ci.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  },
  {
    "reason": "Issue in ci.yml",
    "type": "missing_timeout_minutes",
    "file": "ci.yml",
    "action": "flag",
    "rule_module": "workflow_audit",
    "severity": "medium"
  }
]

Powered by Hypatia Neurosymbolic CI/CD Intelligence