fix(open-knowledge): edit_document / edit_frontmatter / rollback surface disk-persistence failures (PRD-6832)

PRD-6838 made `write_document` await its disk flush and return a storage error
instead of a false "success" when the write fails to reach disk. The other
debounced-store MCP write handlers still returned success the instant the CRDT
transaction committed — so a crash inside the persistence debounce window, or a
swallowed disk failure (ENOSPC / EACCES / read-only FS), silently lost the write
while the agent was told it succeeded.

`edit_document` (agent-patch), `edit_frontmatter` (frontmatter-patch), and
`version` rollback now reuse the same awaited-flush + failure-surfacing pattern:
the handler force-flushes the L1 disk store and, on failure, responds with the
matching storage problem type (507 `storage-full` / 500 `storage-readonly` /
500 `storage-error`) rather than a success. The CRDT copy is still retained in
memory.

`create`, `delete`, `ingest`, and `rename` are unaffected: they write
synchronously (no debounced-store window) and were already durable.

feat(ok): make config self-describing and starter packs cleaner for novices

Configuration is now legible end to end. Every config field carries a
description that flows into the published per-scope JSON schemas, so editors
show inline field help and autocomplete from the `$schema` comment in
`.ok/config.yml`. Config errors (scope violations, agent-not-settable,
mixed-scope writes) now name the exact file to edit and explain the scope in
plain language instead of citing internal codes. `ok init` no longer scaffolds
a dead `folders:` block or a Picomatch cheatsheet, and the schema-reference
path it prints is correct. The docs site configuration reference and quickstart
gain a scope column, the telemetry keys, a tiered env table, and the
three-layer model.

Starter packs are lighter and clearer. Template bodies are now bare headings
(no instructional prose polluting new docs or `log.md`), folder descriptions are
one-liners, and the "frontmatter sweep" jargon is gone. The workflow guidance
that used to live in template bodies now ships as a per-pack project skill:
`ok seed` (and the in-app Initialize dialog) install an
`open-knowledge-pack-<id>` skill next to the platform `open-knowledge` skill for
every editor set up in the project (`.claude`, `.cursor`, `.agents`). Install is
unified server-side in `applySeed`, so the CLI, the desktop IPC path, and the
HTTP path behave identically. Pack skills are now composed into the built CLI
and desktop artifacts, not just resolved from source.

GitOrigin-RevId: a32ab32fb49cec0a0b7a932f9b41a394eb7621e6