Whyve 0.3.0

Breaking. The product version restarts at 0.3.0; the protocol is
context-common/v3 (record schemas context-<kind>/v2, indexes
context-area-index/v2 and context-root-index/v2). See the migration guide.

• A new normative record model (docs/record-model.md),
  from which the runtime model is generated: flat compact-JSON headers, a common
  key, fixed sections with Korean aliases, a final ## Sources list, namespaced
  host headers (howse.thread), YYYY-MM-DD-title.md names (DOCUMENT and TERM:
  title.md), and plain Markdown index rows.
• New host API WhyveHost: capabilities, status, list, searchHeaders,
  read, checkSlot, compare, validateReadReceipt, prepare, apply.
  Writes are prepare → apply(handle); prepare returns prepared,
  needs_approval, needs_review, or needs_archive, and apply is idempotent.
• Meaning is judged by the caller: compare delivers the mandatory records
  (supersede target, slot occupants, typed references) with complete bodies and a
  comparison receipt; prepare requires a same|separate|support|conflict|replace|unclear
  judgment for each. A capture with no mandatory records needs no comparison.
• Missing evidence, rationale, alternatives, success criteria, or summary are
  quality flags, never rejections. Bodies over 256 KiB return needs_archive
  with suggested ARCHIVE chunks.
• Discovery is exact: list filters with coverage and cursors; searchHeaders
  reads header blocks with eq/contains/regex conditions. Lexical recall and
  scoring are removed.
• Authorization is unchanged in spirit: user or configured policy for every
  write. In explicit mode, policy authorization returns needs_approval;
  complete it with prepare({preparedHandle, authorization}).
• Removed: candidates, attestations, assertions and evidence pointers, same-claim
  digests, approval digests and receipt files, *_workflow.mjs, recall,
  search, checkDecision, compareDecision, specView, revisitDecisions,
  owner routing, and area registration.
• context-common/v2 vaults are readable; writing requires
  whyve migrate-project PATH --to-format context-common/v3, with a dry run,
  --apply-plan (backup, journaled apply, verification), and --rollback-plan.
• Skills, rules, templates, managed guidance, and docs describe the new flow with
  JSON input files; the shipped decision examples are executed by the tests.