fix(browse): declare lastConsoleFlushed to restore console-log persistence

[yashkot007]

Summary

flushBuffers() (server.ts:331) maintains a per-buffer cursor for console / network / dialog so it only appends new entries to each on-disk log on every interval tick. The console cursor is referenced + assigned in the function body — but the matching let lastConsoleFlushed = 0; declaration is missing. Only the network and dialog siblings are declared at lines 327-328.

Result: every 1-second flushBuffers tick (line 376) throws ReferenceError: lastConsoleFlushed is not defined, gets swallowed by the catch at line 369 ([browse] Buffer flush failed: …), and the console branch's append never runs. browse-console.log is never written in any production deployment since this regressed.

Root cause

Regression introduced by 1a100a2a "fix: eliminate duplicate command sets in chain, improve flush perf and type safety" — the flush refactor switched from Bun.write to fs.appendFileSync and added the lastConsoleFlushed cursor pattern alongside its network/dialog siblings, but missed the matching let declaration. Tests don't currently exercise flushBuffers, so the regression shipped silently.

How it surfaced

Found while stress-testing the daemon with 15 concurrent CLIs against cold state. The race surfaced this in one spawned daemon's stderr:

[browse] Buffer flush failed: lastConsoleFlushed is not defined
[browse] Buffer flush failed: lastConsoleFlushed is not defined
…repeated every second indefinitely

Verified by running the daemon against a real file:// page with console.log events:

• in-memory ./browse console correctly returns the captured entries
• .gstack/browse-console.log is never created on disk

After the fix, the same flow produces a 163-byte log file with the expected entries.

Fix

+let lastConsoleFlushed = 0;
 let lastNetworkFlushed = 0;
 let lastDialogFlushed = 0;
 let flushInProgress = false;

One line. Same pattern as the existing siblings.

Regression test

Added browse/test/server-flush-trackers.test.ts — a source-level guard following the terminal-agent.test.ts and dual-listener.test.ts pattern (read source as text, assert invariant, no daemon required).

The test extracts every last*Flushed identifier referenced inside flushBuffers() and asserts each one has a matching let X = 0; declaration at module scope. Catches the exact regression class — any future flush-perf refactor that adds a fourth buffer cursor (or copy-pastes the pattern without the matching declaration) will fail this before it ships.

The failure message is intentionally specific so a future contributor sees the fix path without reading the test:

\lastConsoleFlushed` is referenced inside flushBuffers but never declared at module scope with `let lastConsoleFlushed = 0;` — the interval will throw ReferenceError every tick and the corresponding on-disk log will never be written`

Test plan

• New regression test fails on current main (verified before the fix), passes with the fix
• bun test browse/test/server-flush-trackers.test.ts — 1 pass / 0 fail
• bun run build — clean rebuild of all binaries
• Manual smoke — spawn daemon → goto file:// page with console.log → wait 4s for flush interval → .gstack/browse-console.log now exists with the expected entries (163 bytes vs zero file before)

🤖 Generated with Claude Code

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