Improve project action terminal readiness

[Quicksaver]

Summary

This branch tracks the terminal-backed project action work after syncing with the fork's current main and then merging the latest upstream/main. The production behavior is already present on origin/main; the remaining branch-local delta now includes upstream PR review fixes for VS Code bootstrap/webview safety and command-output merging, test compatibility cleanup in apps/server/src/terminal/Manager.test.ts, one focused project-action terminal readiness hardening patch, and the latest upstream mainline merge.

The underlying project action behavior still routes actions through stable action-specific terminals, waits for the selected terminal to be input-ready before writing, avoids busy terminals when choosing a target, and keeps POSIX subprocess detection conservative when process-tree inspection cannot prove the shell is idle.

What Changed

• Reuses stable encoded action-* terminal IDs for project scripts, with numeric fallback suffix allocation when existing action terminals are busy.
• Waits for input readiness through terminal output/attach state before writing project-action commands, timing out instead of hanging indefinitely.
• Avoids reusing busy action terminals and keeps fallback action terminal IDs separate from script IDs such as action-build-2.
• Uses readable fallback labels such as Action: build (2) so fallback instances do not collide visually with primary action terminals.
• Keeps POSIX subprocess detection conservative when process-tree inspection fails, while allowing proven idle login shells to be reused.
• Keeps focused coverage for action terminal ID selection, fallback collision avoidance, prompt readiness, idle-shell detection, conservative ps fallback behavior, and action terminal labels.
• After the latest mainline sync, updates Manager.test.ts compatibility by referencing TerminalManager.__testing through the existing namespace import and avoiding the unstable ChildProcessSpawner.ExitCode import in test output helpers.
• Treats an attach stream ending before input readiness as a typed strict-readiness failure, while preserving the best-effort UI path that still writes after readiness failures.
• Addresses Macroscope and Cursor review findings by sanitizing VS Code workspace bootstrap 500 responses, preserving malformed readiness diagnostics while keeping transient body-read retries bounded, disposing webview resources on render failure without masking the render error, cleaning MCP bridge socket resources on listen failure, escaping case-insensitive inline script closing sequences, trimming Codex file-change kind strings, and avoiding duplicate/truncated command-output prefix merges including multiline strict-prefix snapshots.

Why

When running a custom action, the terminal can open and receive the inserted action before the shell is ready. Once the terminal later becomes ready, it may no longer be able to receive that action. The project action path therefore needs to wait for an input-ready prompt, reuse stable action terminals only when they are genuinely usable, and fail conservatively when terminal busy/idle state cannot be proven.

This branch is now mostly preservation and review history for behavior already carried by the fork's mainline, plus upstream PR review fixes, the small test/readiness compatibility deltas needed after the latest main sync, and the current upstream mainline merge.

No per-branch CUSTOMIZED.md is present. That merge-maintenance inventory is intentionally branch-local to main.

Validation

• Previously run: pnpm exec vp check
• Previously run: pnpm exec vp run typecheck
• Previously run: pnpm exec vp test run apps/web/src/projectScriptTerminals.test.ts apps/server/src/terminal/Layers/Manager.test.ts packages/shared/src/terminalLabels.test.ts
• Previously run: pnpm exec vp test run apps/server/src/terminal/Layers/Manager.test.ts packages/shared/src/terminalLabels.test.ts apps/web/src/projectScriptTerminals.test.ts
• Latest run: pnpm exec vp test run apps/web/src/session-logic.test.ts apps/vscode-extension/src/backendManager.test.ts apps/vscode-extension/src/webview.test.ts apps/vscode-extension/src/mcpBridge.test.ts apps/vscode-extension/src/extension.test.ts
• Latest run: pnpm exec vp check
• Latest run: pnpm exec vp run typecheck
• Assessment follow-up also reran focused session-logic, backendManager, webview, and mcpBridge tests plus vp check and vp run typecheck after the review-hardening commits.
• Latest Cursor follow-up run: pnpm exec vp test run apps/web/src/session-logic.test.ts
• Latest Cursor follow-up run: pnpm exec vp check
• Latest Cursor follow-up run: pnpm exec vp run typecheck
• Latest run: pnpm exec vp test run apps/web/src/projectScriptTerminals.test.ts
• Latest run: pnpm exec vp check
• Latest run: pnpm exec vp run typecheck

Review Follow-up

• Fixed Cursor Bugbot's POSIX subprocess test mock comment by making the ps mock distinguish the direct child command lookup from the full process-table lookup.
• Fixed Cursor Bugbot's duplicate action tab label comment by formatting fallback action terminal instances with a parenthesized suffix, so action-build:2 renders differently from action-build-2.
• Ran CodeRabbit, Codex, Blast, final CodeRabbit, and final Codex assessment passes; Blast suggested additional test hardening, which was committed in f4a01d8214347a69ced926fde34354e3dfd3aa12.
• Synced the branch with origin/main; the current branch-local diff over origin/main is the Manager.test.ts test compatibility cleanup described above.
• Fixed Macroscope's six new review threads in commits fd6a6d884, 8bc52982, ade76fe93, 490454e1, and 8abfd42e, then ran the required CodeRabbit, Codex, Blast, final CodeRabbit, and final Codex assessment sequence for those changes.
• Fixed Cursor Bugbot's multiline stdout prefix duplication thread in fc153e138, preserving shorter multiline prefix snapshots without dropping ambiguous one-character streamed chunks, then ran CodeRabbit, Codex, Blast, final CodeRabbit, and final Codex assessment passes. CUSTOMIZED.md was later removed from this branch in 3046aa4a0 because it is intentionally branch-local to main only.
• Replied to and resolved Macroscope's stale CUSTOMIZED.md path-reference thread without code or doc changes, because CUSTOMIZED.md is absent from this branch.
• Merged the latest upstream/main through 6e48d8093; no additional validation was run because this was a merge-only PR metadata refresh.

Proof

• No screenshots, screencasts, or log files were added.

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Note

High Risk
Touches orchestration persistence and provider interrupt paths for subagents, auth compatibility endpoints, and desktop backend discovery advertisements—areas where regressions affect thread lifecycle, security sessions, and multi-client connectivity.

Overview
This PR is a large fork/integration batch rather than a single feature: it wires Codex subagent lineage through orchestration projection (parentRelation / subagent columns on thread create/update and snapshot queries), child-thread runtime ingestion (shell creation, launch prompts, resume-to-running, title generation), and interrupt routing through the root provider session with explicit failure when no child turn exists.

Host and desktop: Server config gains VS Code-oriented bootstrap fields (workspace folders, active folder key, host MCP servers, hostIntegration), plus t3 stdio-to-uds for MCP stdio relay. Legacy HTTP routes restore bearer bootstrap and session revoke compatibility. Desktop backend runs now write and heartbeat backend advertisements in t3Home, refresh them on readiness, and remove them on run finalization/stop (with a regression test). Electron context menus collapse duplicate leading/trailing separators.

Docs and agent workflow: New maintainer docs (SUBAGENTS.md, SOURCE_CONTROL.md, POWER_CONSUMPTION.md) and .agents/skills/* orchestration skills for updating/porting worktrees and addressing PR comments from parallel branches. AGENTS.md notes the fork and CUSTOMIZED.md.

Misc: Auth/session test hooks (deleteExpired, stale desktop bootstrap bearer cleanup policy), sanitizeErrorCause for bounded diagnostics, mobile EAS owner/project id change, .gitignore for *.vsix, and assorted mock/test harness updates (ACP/Codex cwd logging, integration text-generation layer ordering).

^{Reviewed by Cursor Bugbot for commit 2a02f76. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Add VS Code extension, source control panel, and subagent thread hierarchy support

• Introduces a new VS Code extension (apps/vscode-extension/) with a webview renderer, BackendManager for desktop backend connectivity, a Unix-socket MCP bridge, client settings persistence, and virtual workspace cache for GitHub virtual folders.
• Adds a SourceControlPanelService and SourceControlPanel UI with comprehensive VCS operations (staging, committing, pull/push, branch management, diff rendering), exposed via new vcsPanel* WebSocket RPCs and scoped by auth.
• Implements subagent thread hierarchy throughout the stack: orchestration now cascades deletes/archives to subagent descendants, provider runtime ingestion creates child threads from collab events and routes notifications to deterministic child thread IDs, and the sidebar and messages timeline render hierarchical thread rows with status and live duration.
• Improves project action terminal readiness in ChatView by reusing existing sessions when idle, waiting for readiness before sending input, and closing terminal UIs when terminals are disabled by host preferences.
• Adds host appearance and display preferences (hostAppearance.ts, hostDisplayPreferences.ts) so VS Code webviews can override the app theme, fonts, and thread conversation width via window.t3HostBridge.
• Risk: database migration 033 adds parent/subagent relation columns to projection_threads; migration 034 backfills root_thread_id for existing rows, which may be slow on large databases.

^{Macroscope summarized 6e48d80.}