fix(acp): populate ToolCall title and raw_input from tool params

[bug-ops]

Problem

All bash tool calls in the Zed ACP chat showed only bash as the title,
making it impossible to see which command was being executed without
expanding "View Raw Input".

Root Cause

LoopbackEvent::ToolStart carried only tool_name and tool_call_id.
In loopback_event_to_updates the title was set to tool_name ("bash")
with no command information attached.

Changes

• LoopbackEvent::ToolStart — new params: Option<serde_json::Value> field
• send_tool_start trait method and LoopbackChannel implementation updated
• tool_execution.rs — passes tc.input as params at the call site
• loopback_event_to_updates — derives ToolCall.title from command /
  path / url keys in params (truncated to 120 chars with … suffix);
  attaches params as raw_input for "View Raw Input"
• permission_denied_returns_blocked_error test — uses isolated temp file
  to prevent cache pollution from bash = "allow" in the default config

Result

Zed now shows the actual command in the tool call bubble:

Run Command
gh api repos/agentclientprotocol/…/contents/docs --jq '.[] | …'

Commands longer than 120 characters are truncated with ….

Test plan

• cargo clippy --workspace -- -D warnings passes
• All 2921 tests pass