v0.4.0

GitHub App auth for the bot, multi-user attribution, Slack UX overhaul, experimental `/console`, two new community providers (OpenCode and GitHub Copilot), Codex MCP support, and broad workflow/provider hardening.

### Added

- **GitHub App authentication for the bot**: replaces the shared `GITHUB_TOKEN` PAT with a GitHub App + multi-installation routing. Each repo resolves to the installation that owns it; tokens are minted on demand, cached per installation, refreshed before expiry, and never persisted. Includes a loopback-only `/internal/git-credential` endpoint (with a hard `127.0.0.1` bind check, opt-out via `ARCHON_ALLOW_INTERNAL_ON_PUBLIC_BIND=1`) so long-running workflow `git` operations can transparently refresh installation tokens via a `git-credential-archon` helper installed into the worktree's `.git/config` (#1788).
- **Per-user attribution**: `user_id` is now plumbed from chat and forge adapters through the orchestrator into `conversations`, `messages`, `workflow_runs`, and `isolation_environments`. New `users` and `user_identities` tables map platform identities (Slack U-id, Telegram chat id, Discord snowflake, GitHub login) to an Archon-internal user, created lazily on first sight (#1783).
- **Slack UX upgrade**: interactive buttons, status reactions, and native slash commands replace the previous text-only flow. Approval gates, run status, and errors are now surfaced through Slack's UI primitives (#1757).
- **Experimental run-centric console UI** at `/console`, mounted as an isolated in-repo spike under `packages/web/src/experiments/console/`. Lint-guarded against importing production web modules so it can be dropped in or deleted cleanly (#1747).
- **`assistants.opencode` provider**: community provider that runs OpenCode as an embedded runtime, with per-node agent materialization, multi-agent sessions, structured output, token usage, and multi-agent MCP tool execution (#1384).
- **GitHub Copilot community provider**: registered as a `builtIn: false` provider in the registry (#1505).
- **Codex MCP nodes**: MCP server support for Codex workflow nodes via the shared `loadMcpConfig` module — pass `mcp: <path>` on a Codex node and the config is translated to Codex's `mcp_servers` overrides at runtime. MCP client errors are surfaced to the workflow author as `system` chunks when MCP is explicitly configured for the node (#1459).
- **`always_run` node opt-out for resume caching**: opt-out for nodes that must re-execute on every resume rather than being skipped as "already completed" (closes #1391, #1730).
- **Pi deferred extension model resolution** so Pi workflows can reference models that are only available after extension loading (#1509).
- **Brand foundation page** at https://archon.diy/brand/, sourced from `packages/docs-web/src/content/docs/brand/` (#1745).
- **New marketplace workflows**: `piv-system-evolution` and `archon-comprehensive-mr-review`.

### Changed

- **Streaming chat continuity**: typing indicators and message boundaries are more readable; rapid successive chunks no longer fragment visually (#1617).
- **Web chat bubbles** wrap long unbreakable strings instead of overflowing (fixes #1738, #1742).
- **Web DAG builder** recognizes `loop` and `approval` node types and renders them correctly (#1744).
- **Web execution graph** surfaces workflow-definition fetch errors instead of silently rendering an empty graph (#1683, #1698).
- **Web copy-message button** handles clipboard failures gracefully (#1564).
- **Telegramify-markdown** bumped to 1.3.3 for correct blockquote escaping (#1340).
- **Webhook clones** are placed in the workspace `source/` subdirectory to match the standard workspace layout (#1554).
- **Global workflows** are now editable through the Web UI builder (#1557).
- **`safeSendMessage`** consolidated into `executor-shared` to remove duplication across executor variants (#1496).
- **Direction docs**: community-providers policy section added (#1736).

### Fixed

- **`workflow approve/resume/reject` no longer fail with "Workflow not found" when the run's working path is a worktree or workspace clone.** Resume, approve, and reject now use `codebase.default_cwd` for workflow YAML discovery, falling back to `working_path` when no codebase record is found. Fixes #1663 (#1743).
- **Resume interactive workflows on chat platforms**: previously failed because the resume code path assumed web; now works for Slack and Telegram (#1756).
- **Web approve/reject responses** surface the CLI resume command so users can copy it directly instead of having to look it up (#1523).
- **`DEFAULT_AI_ASSISTANT`** is now read in `createCodebase` so the env var actually controls the default assistant for newly registered codebases (fixes #1703, #1746).
- **Marketplace `decide` node** hardened against non-JSON ai-review output so a prose-prefixed verdict doesn't crash the workflow.
- **MCP config env vars** now expand `${VAR_NAME}` brace syntax in addition to `$VAR_NAME` (#1728).
- **`archon-refactor-safely`** persists read-only node outputs via bash bridges so downstream nodes can reference them (#1734).
- **Workflow builder** injects `$ARGUMENTS` into generated YAMLs so user arguments reach the first node (#1733).
- **Codex provider**: removed stale `attemptController.abort()` that crashed after SDK cleanup (#1735, #1739); fresh `AbortController` per retry attempt so a previously-aborted controller can't kill the new attempt (#1266, #1371).
- **Claude provider** rejects directory paths in `claudeBinaryPath` and expands npm platform-package directories (e.g. `@anthropic-ai/claude-code-darwin-arm64`) to the bundled binary (#1723, #1737).
- **Default assistant resolution**: now consults config + per-folder detection on every codebase registration, not just the first (#1729).
- **Large node outputs** are written to a temp file and referenced rather than inlined into bash substitution, preventing argument-list corruption on big payloads (fixes #1717, #1718).
- **Forge clone auth** resolves credentials via configured `*_URL` env vars rather than assuming `github.com` (fixes #1704, #1706); non-GitHub forge URLs authenticate via `GITLAB_TOKEN` / `GITEA_TOKEN` (fixes #1655, #1658).
- **DAG multi-resume**: completed node state is now preserved across multiple resume cycles instead of being recomputed (#1530).
- **Bash node variables**: user-controlled variables are passed via env vars, not shell substitution, to avoid quoting bugs and injection edge cases (#1651).
- **Scripts**: `ARCHON_STATE_JSON` marker extraction uses line-anchored regex so embedded marker-like strings in script output don't confuse the parser (#1695).
- **Workflows**: `condition_json_parse_failed` is now surfaced as a workflow error instead of silently skipping the conditional branch (#1673, #1694).