Name templated benches after their template and invite the roster

[TheGreatAxios]

What was broken

Driving the app live (sign in, "New workbench", pick Code review, create), two bugs surfaced that no test caught:

1. The bench was named "New Workbench", not "Code review". createWorkbenchFromTemplate (apps/web/src/instant-agent-create.ts) unconditionally passed NEW_WORKBENCH_TITLE as the room's name, even though the picked template's manifest already carries its own title ("Code review"). Every templated bench looked identical in the sidebar.

2. Myra's greeting says "Three reviewers read every pull request and post what they'd change," but the room held only Myra. instantiateWorkbenchTemplate (packages/workflow-catalog/src/instantiate.ts) created the three reviewer agent-directory definitions but never added them as room participants — its own doc comment said as much: "inviting the reviewers into the room… are the next slice." Confirmed by reading the code, not by driving the app a second time: POST /workbenches/:id/invite (@corbits/chat-ui's inviteAgent) is the only route that actually joins an agent to a room, and nothing on the template-create path ever called it.

Which of the two possibilities #2 turned out to be

Not "the reviewers join later, after GitHub connects" — there's no such deferred-join mechanism anywhere in the create or connect-GitHub path. It was purely a missing slice: the reviewers are meant to be present immediately (their agent definitions get created synchronously, in the same request), the room just never invited them. So the fix invites them, rather than rewriting the greeting to describe a future state.

The fix

• apps/web/src/instant-agent-create.ts: name: manifest?.title ?? NEW_WORKBENCH_TITLE — a named template names the bench; the blank template ("Just start talking") keeps the generic title, since there's nothing better to call it.
• packages/workflow-catalog/src/instantiate.ts: instantiateWorkbenchTemplate now calls a new inviteParticipantAgent(id) port for every non-Myra participant right after resolving its agent-directory id — whether that id came from a fresh createParticipantAgent call or an already-existing definition. (An agent definition already existing tenant-wide is not the same as already being a participant of this new room, so a skipped create still needs an invite.) listAgentHandles now returns {handle, id} pairs instead of bare handles, since the id is what the invite call needs.
• apps/web/src/instant-agent-create.ts wires the new port to inviteAgent from @corbits/chat-ui (POST /workbenches/:id/invite), the same call the existing "Invite agent" dialog and "Add Jimmy" quick-create already use.

What a first-time user now sees after picking "Code review"

The bench is named "Code review" in the sidebar, and the room opens with Myra plus all three reviewers already present as participants — matching exactly what Myra's greeting promises.

Ticket-worthy detail (Linear MCP was disconnected while writing this PR)

Found but out of scope for this fix: the picker row's copy ("Three reviewers read every pull request and post what they'd change.") is duplicated as a static literal in apps/web/src/workbench-templates.ts, separate from the live catalog manifest's promise field that the in-room greeting reads (packages/workflow-catalog/src/templates.ts). PR #275 made the greeting read live; the picker row itself still has to be hand-kept in sync. Worth a follow-up ticket to have the picker read the same live value instead of a second hardcoded copy.

Test plan

• bun test in packages/workflow-catalog — 13 pass, including new coverage that every reviewer (created or already-existing) gets invited, and Myra never is.
• bun test in apps/web (instant-agent-create.test.ts) — 2 pass: blank template keeps the generic title; code-review template names the bench "Code review" and invites all three reviewers with the ids their create calls returned.
• tsc --noEmit clean in both packages.
• eslint clean on the four changed files.
• prettier --write run on changed files.