Add play button to run the session's main project

[AThraen]

Summary

Add a "play" / run button to the session toolbar that executes a configurable command in the session's terminal. Per-project (or per-language/per-framework) configuration so the button does the right thing for each working folder.

Motivation

When a session is open on a project folder, the most common follow-up action is to run / start / build it. Today this means typing dotnet run, npm start, cargo run, python main.py, etc. by hand. A one-click "play" button would cut that to a single keystroke and make CodeShellManager feel more like an IDE harness.

Proposed behavior

• New play (▶) button on the per-session toolbar (next to the existing 💤 / ✕ controls).
• Click sends a configured command to the active terminal (as if typed + Enter), so output streams normally and indexing/alert detection still works.
• Disabled / hidden when no run command is configured for the session.

Configuration

Per-session run command, persisted on ShellSession:

• RunCommand: string? — explicit override (highest priority)
• Fall back to project-type detection on WorkingFolder:
  • *.sln / *.csproj → dotnet run
  • package.json with a start script → npm start (or pnpm / yarn / bun if their lockfile is present)
  • Cargo.toml → cargo run
  • pyproject.toml / requirements.txt → python main.py (configurable)
  • Makefile with a run target → make run
• Settings page entry to add / edit project-type → command mappings (similar to CommandPresetsService).
• Right-click on the play button → "Configure run command…" opens an editor for that session.

Open questions

• Should the play button confirm before sending if a command is already running in the terminal?
• Should there be a global keybinding (Ctrl+R / F5)?
• For SSH sessions, run command is sent over the existing PTY — same path, just verifying it works.

Out of scope

• Build vs run vs test split (would be a follow-up — possibly a small dropdown next to play).
• Spawning a separate terminal to host the run process (current proposal reuses the active terminal).

[AThraen]

On the left session bar it should be added to the right-click menu as a sub-menu "Session commands" or something like that. On the session it can be a play button in the top bar - but if there is more than 1 command (configurable) there could be a drop-down next to it and list the others. We should find a nice way to configure it.

[AThraen]

If the "play" starts a process, we should keep track of the process tarted and have an X option to kill it (with confirmation dialog)

[AThraen]

Implementation status — feat/run-commands (not yet merged)

The feature has shipped on the feat/run-commands branch and is documented under "Per-Session Run Commands" in CLAUDE.md. Summary of what's in vs. the original proposal:

Implemented

• ▶ Run button on the terminal toolbar with a ▼ dropdown when there's more than one command
• Per-session list of labelled commands (List<RunCommandItem> on ShellSession, persisted to state.json) with a single-default invariant
• Project-type seeding on new sessions: dotnet → cargo → node → python → make (first match wins, top-level scan only)
• F5 runs the active session's default; Shift+F5 stops it
• Sidebar right-click → "Session commands" submenu (matches @AThraen's first comment)
• Editor dialog (SessionRunCommandsDialog) — inline edit, reorder, +Add / 🗑, default-radio column
• Chips strip between toolbar and terminal (blue=running, green=ok, pink=failed) → click opens a drawer with [⏹ Stop] [📋 Copy] [↗ Send to terminal]
• Process lifetime: runs are killed on session close, sleep, and app exit. Uses JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE so the whole child tree dies with the PTY.

Notable divergence from the proposal

• Runs in a separate headless PseudoTerminal rather than typing into the active terminal. Rationale: a Claude session shouldn't be polluted by dotnet run output, and we wanted output captured/scrollable independently. "Send to terminal" is still available from the drawer — for Claude parents it wraps in a fenced preamble; for non-Claude shells it falls back to clipboard with a toast (auto-paste would execute pasted lines).
• Multiple labelled commands per session, not a single RunCommand: string?.

Open items from the comments

• @AThraen suggested the kill action confirm before terminating a running process. Currently the drawer's ⏹ Stop button kills immediately with no prompt — happy to add a confirm if you want it.

PR will follow once the branch is reviewed.

[AThraen]

Shipped on feat/run-commands — see the implementation status comment above for details and divergences. PR to follow.

[AThraen]

Shipped in v0.5.0.