fix(web): read committed .deco snapshots so CMS works without dev server

[guitavano]

Summary

Makes the Content tab (CMS) available and editable without a running dev server, by reading the committed .deco/ snapshots straight from the sandbox working tree, and fixes a latent stripLineNumbers bug that was silently truncating large file reads.

CMS without the dev server

• useDecofile / useLiveMeta now read the committed .deco/blocks.gen.json (decofile) and .deco/meta.gen.json (live meta) via the daemon file-read proxy (/read) when the dev server is down, falling back to it even when the route errors (crashed dev script). The live /.decofile + /live/_meta routes still win once the dev server is up.
• Single cache per key (KEYS.decofile / KEYS.liveMeta): the committed snapshot seeds it, so the existing optimistic block writes (which already persist to the FS via /write + /unlink) operate on a full base.
• On the sandbox lifecycle running transition, the CMS queries are re-invalidated so they swap from the committed snapshot to the live routes.
• content-browser passes fetchEnabled: devServerReady so it prefers committed while the dev server is down.

stripLineNumbers truncation fix

The daemon's /read returns line-number-prefixed content. stripLineNumbers used a (.*) capture whose . does not match \r, U+2028, or U+2029. A single-line minified JSON payload with an embedded line separator (common in pasted rich-text content) was truncated at the first such char — an ~11MB decofile was cut in half, breaking JSON.parse. Switched to a prefix-only replace that preserves the rest of each line verbatim. This also fixes the same latent corruption in the file explorer.

Testing

• tsc, lint, fmt clean.
• Verified end-to-end in the app: with the dev server paused, the 11MB .deco/blocks.gen.json now parses fully and the Content tab appears (diagnosed via temporary logging, since removed).

Notes / known limits

• Requires the sandbox daemon to be reachable. A fully paused/suspended sandbox (pod frozen) still can't serve /read, so the tab won't show until resume — separate follow-up (read committed files from git directly).
• Read source is the aggregate blocks.gen.json, which the dev server regenerates; while the dev server is down, a reload won't reflect just-written blocks until it regenerates.

🤖 Generated with Claude Code

---

Summary by cubic

Make the CMS Content and Blocks editors, plus the preview URL-bar pages/global list, work without the dev server by reading committed .deco snapshots. Also fixes a file-read bug that could corrupt large JSON files.

• New Features

  • Read committed .deco/blocks.gen.json and .deco/meta.gen.json when the preview is down or live routes fail; used for the Content tab, Blocks editor, and Preview URL-bar lists before the dev server is up.
  • Added readCommittedJson; useDecofile/useLiveMeta prefer committed data until devServerReady, and the lifecycle running transition now invalidates queries to swap to live routes.
  • Treat crashed as recoverable so the Blocks editor stays available; ungated fetch params in Blocks panel and Preview while keeping fetchEnabled: devServerReady for live routes.

• Bug Fixes

  • stripLineNumbers now uses a prefix-only replace to avoid truncating lines with \r, U+2028, or U+2029`, fixing corruption in large files.

^{Written for commit caf2f49. Summary will update on new commits.}