Add per-project sandbox mode and Bedrock service-tier

Sandbox mode: new per-project toggle that turns on Claude Code's bash
sandbox inside the container. Adds `bubblewrap` and `socat` to the
Dockerfile (the two Linux deps required by the sandbox), and emits a
managed `sandbox` block into `~/.claude/settings.json` via the existing
CLAUDE_CODE_SETTINGS_JSON entrypoint merge:

- `enabled` mirrors the Triple-C toggle and is always emitted, so the
  entrypoint's recursive jq merge clears any prior on-state from the
  persisted named volume — Triple-C is authoritative.
- `enableWeakerNestedSandbox: true` because we run inside Docker without
  privileged user namespaces.
- `allowUnsandboxedCommands: false` to disable the `dangerouslyDisableSandbox`
  escape hatch — opting into the sandbox shouldn't come with a runtime
  bypass.

When sandbox is on, a SANDBOX_INSTRUCTIONS section is appended to
CLAUDE_INSTRUCTIONS so Claude can guide users through allowing extra
paths/domains, excluding `docker *`/`watchman *` from the sandbox, and
the rule that `sandbox.enabled` is owned by Triple-C. The Claude-Code
settings fingerprint includes sandbox state (only when on, to avoid
spuriously flagging existing containers for recreation on upgrade).

Bedrock service tier: new optional field on the per-project Bedrock
config. When set, exported as ANTHROPIC_BEDROCK_SERVICE_TIER (added in
Claude Code 2.1.122) and included in the Bedrock fingerprint.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/src-tauri/src/models/project.rs

@@ -73,6 +73,8 @@ pub struct Project {
     pub openai_compatible_config: Option<OpenAiCompatibleConfig>,
     pub allow_docker_access: bool,
     #[serde(default)]
+    pub sandbox_mode_enabled: bool,
+    #[serde(default)]
     pub mission_control_enabled: bool,
     #[serde(default = "default_full_permissions")]
     pub full_permissions: bool,
@@ -159,6 +161,10 @@ pub struct BedrockConfig {
     pub aws_bearer_token: Option<String>,
     pub model_id: Option<String>,
     pub disable_prompt_caching: bool,
+    /// Optional value for the `ANTHROPIC_BEDROCK_SERVICE_TIER` env var
+    /// (e.g. "priority"). Empty/None means leave unset.
+    #[serde(default)]
+    pub service_tier: Option<String>,
 }
 
 /// Ollama configuration for a project.
@@ -199,6 +205,7 @@ impl Project {
             ollama_config: None,
             openai_compatible_config: None,
             allow_docker_access: false,
+            sandbox_mode_enabled: false,
             mission_control_enabled: false,
             full_permissions: false,
             ssh_key_path: None,