Introduce worktree trust mechanism (#44887)

Closes https://github.com/zed-industries/zed/issues/12589 

Forces Zed to require user permissions before running any basic
potentially dangerous actions: parsing and synchronizing
`.zed/settings.json`, downloading and spawning any language and MCP
servers (includes `prettier` and `copilot` instances) and all
`NodeRuntime` interactions.
There are more we can add later, among the ideas: DAP downloads on
debugger start, Python virtual environment, etc.

By default, Zed starts in restricted mode and shows a `! Restricted
Mode` in the title bar, no aforementioned actions are executed.
Clicking it or calling `workspace::ToggleWorktreeSecurity` command will
bring a modal to trust worktrees or dismiss the modal:

<img width="1341" height="475" alt="1"
src="https://github.com/user-attachments/assets/4fabe63a-6494-42c7-b0ea-606abb1c0c20"
/>

Agent Panel shows a message too:

<img width="644" height="106" alt="2"
src="https://github.com/user-attachments/assets/0a4554bc-1f1e-455b-b97d-244d7d6a3259"
/>

This works on local, SSH and WSL remote projects, trusted worktrees are
persisted between Zed restarts.
There's a way to clear all persisted trust with
`workspace::ClearTrustedWorktrees`, this will restart Zed.

This mechanism can be turned off with settings:
```jsonc
"session": {
  "trust_all_worktrees": true
}
```
in this mode, all worktrees will be trusted by default, allowing all
actions, but no auto trust will be persisted: hence, when the setting is
changed back, auto trusted worktrees will require another trust
confirmation.

This settings switch was added to the onboarding view also.

Release Notes:

- Introduced worktree trust mechanism, can be turned off with
`"session": { "trust_all_worktrees": true }`

---------

Co-authored-by: Matt Miller <mattrx@gmail.com>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
Co-authored-by: John D. Swanson <swanson.john.d@gmail.com>

Cargo.lock

@@ -12421,6 +12421,7 @@ dependencies = [
  "context_server",
  "dap",
  "dap_adapters",
+ "db",
  "extension",
  "fancy-regex",
  "fs",