Advance development main to 0.6.12 and carry its release text (#1558)

Development main now carries the published 0.6.12's versions and release text.

- **Versions:** root, `packages/cli`, `packages/daemon` and `packages/ui` read 0.6.12, and the lockfile matches; `packages/tui` stays 0.1.0.
- **Release text:** the 0.6.12 CHANGELOG section and whats-new entry as published, and `docs/releases/v0.6.12.md`, the published release notes byte for byte.
- **Capability map:** 0.6.12's additions (for example `rig seat set-effort` and `rig usage cost`) alongside main's later entries (`rig seat set-cwd`, the adopted-seat restart note, Pi effort and `rig usage top`).
- **Installer pins:** the README and getting-started now name `v0.6.12`, keeping the standard-user Mac Node route.

The release's two text and version commits are cherry-picked with `-x`; this isn't a merge of `release/0.6.12`, whose source changes main already has whole.

README.md

@@ -22,11 +22,11 @@ Not setting this up today? Get the next walkthrough and occasional OpenRig updat
 
 Requires Node.js 22 or 24 and tmux, on macOS or Linux, and one working Claude Code or Codex account: one is enough, since the kernel operator adapts the shipped `starter` team to whichever you have. On Linux, the distribution's own Node.js can be older (Ubuntu 24.04's is 18); install a supported version with [nvm](https://github.com/nvm-sh/nvm) (`nvm install 22`) or NodeSource. On a Mac with Apple silicon, use Node.js 22 ([compatibility history](docs/releases/v0.5.15.md#known-compatibility-limitation)). On a Mac where you aren't an administrator, or where Homebrew belongs to another account (its `brew install` is refused), install Node.js in your own home folder with [nvm](https://github.com/nvm-sh/nvm): run `touch ~/.zshrc` (a new Mac account has none, and nvm's installer only adds itself to a profile file that already exists), then the install command on nvm's page, open a new terminal, and run `nvm install 22`. That needs no administrator password, and `npm install -g` then installs into your nvm folder. On Windows, use WSL2, the Windows route OpenRig supports; native Windows isn't supported. OpenRig's automated tests don't run on WSL2 yet; see [one user's working setup](docs/reference/getting-started.md#wsl2-a-reported-working-setup). Launching a rig writes provider hooks and workspace trust settings. Before running the commands below, read [what OpenRig changes on your machine](#what-openrig-changes-on-your-machine) and back up the relevant files.
 
-**One command.** This runs OpenRig's install script from the `v0.6.11` release. It checks Node.js and npm, installs the latest published `@openrig/cli` with `npm install -g`, runs the Node.js and SQLite check, then runs `rig setup --dry-run` and `rig setup`. The first line prints that plan and changes nothing:
+**One command.** This runs OpenRig's install script from the `v0.6.12` release. It checks Node.js and npm, installs the latest published `@openrig/cli` with `npm install -g`, runs the Node.js and SQLite check, then runs `rig setup --dry-run` and `rig setup`. The first line prints that plan and changes nothing:
 
 ```bash
-curl -fsSL https://raw.githubusercontent.com/mvschwarz/openrig/v0.6.11/scripts/install.sh | sh -s -- --dry-run
-curl -fsSL https://raw.githubusercontent.com/mvschwarz/openrig/v0.6.11/scripts/install.sh | sh
+curl -fsSL https://raw.githubusercontent.com/mvschwarz/openrig/v0.6.12/scripts/install.sh | sh -s -- --dry-run
+curl -fsSL https://raw.githubusercontent.com/mvschwarz/openrig/v0.6.12/scripts/install.sh | sh
 ```
 
 If a provider isn't signed in yet, the last step reports `FAILED [4/4]`, and `rig setup` lists the sign-in under "Some steps need attention". If the only remaining failures are provider sign-ins, the install steps finished; sign in to each selected provider as below and continue.