Addresses T1 review: discovery.ts logs mDNS bind errors to stderr and returns
already-found devices instead of masking failures as empty; spend-flow uses a
collision-proof "other" sentinel and a local-date period label; the spend/date
flags get friendly error handling; devices-json tests are deterministic (mocked
discovery) and assert the read-only mutation guards. 13 tests green, tsc clean.
Implemented by Codex gpt-5.5 (high); committed by Fable (git blocked in Codex sandbox).
New `codeburn spend --format flow-json` emits the model x project cost matrix
(uncapped, then top-8 each side with an "other" rollup) for the desktop Spend
Sankey. Adds --format json to devices / devices scan / share status / identity,
matching the web /api/* shapes. Read-only; text output unchanged when --format
is omitted. discovery.ts degrades mDNS bind errors to an empty scan result.
Implemented by Codex gpt-5.5 (high); committed by Fable (git was blocked in the Codex sandbox).
