v0.1.21-rc1

Prerelease for the RL harness. Adds BCODE_FETCH_USE_ENDPOINT (#157), which
lets a caller mediate fetch-use so a sandboxed agent never holds the real
BROWSER_USE_API_KEY.

Hyphenated tag, so the release workflow marks it --prerelease and not
--latest: the install one-liner keeps resolving v0.1.20 unless a version is
pinned explicitly.

Merge pull request #150 from browser-use/rollover-regression

test(opencode): cover message ID rollover loop

Merge pull request #148 from browser-use/claude/cold-startup-times-cd…

…25a7

feat(bcode-serve): serve-only binary variant for headless containers

Merge pull request #145 from browser-use/hosted-curl-quickstart

docs: advertise the hosted v4 API in the README

Merge pull request #139 from browser-use/clarify-timed-out-invocation

Clarify browser timeout continuation semantics

Merge pull request #136 from browser-use/timeout-recovery

fix(browser): preserve session after tool timeout

Merge pull request #129 from browser-use/provisioned-auto-attach

fix(browser): auto-attach provisioned sessions

Merge pull request #127 from browser-use/fireworks-image-overflow

fix(llm): compact on provider image limits

Merge pull request #117 from browser-use/rebrand-sync-additions

fix(core): rebrand attribution headers and meta prompt introduced by v1.18.4 sync

BrowserCode v0.1.13. Restores bcode.db database filename after upstre…

…am database ownership move.