docs: Mismatch between agent documentation and current functionality. The name field is no longer optional.

[JonathanBerkeley]

Documentation file agent-format.md specifies the agent field "name" to be optional.

The "name" field for an agent has become mandatory since this commit:
dc0974f#diff-61df6179f46d679df0c7da318067babd72d265d8958e1b94e3a990de0bfba45fL123-L124

The "/agent generate" command also requires providing a name:
a8afb47#diff-f6d402f6ca61a5601d188759a5d5246ceb57016fa6744f5bbbdec85180ff7a2cR1606

Attempting to use an agent json file with no "name" field results in the following on Q startup:

mainuser@mainpc:~$ q
Error: Json supplied at /home/mainuser/.aws/amazonq/cli-agents/santas-little-helper.json is invalid: missing field `name` at line 7 column 1

Similarly, for "/agent generate":

> /agent generate

✔ Enter agent name:  ·
✔ Enter agent description:  · example
✔ Agent scope · Global (all workspaces)

Agent name and description cannot be empty.

Then in other documentation which gives examples of agent usage, it lacks the "name" field. Following these examples will give the same error:

mainuser@mainpc:~/example_project$ mkdir -p .amazonq/cli-agents
cat > .amazonq/cli-agents/project-helper.json << 'EOF'
{
  "description": "Helper agent for this specific project",
  "tools": ["fs_read", "fs_write", "execute_bash"],
  "resources": [
    "file://README.md",
    "file://docs/**/*.md"
  ]
}
EOF
mainuser@mainpc:~/example_project$ q
Error: Json supplied at /home/mainuser/example_project/.amazonq/cli-agents/project-helper.json is invalid: missing field `name` at line 8 column 1

[JonathanBerkeley]

PR created to update docs: #3232