fix(chat): make --no-interactive truly non-interactive

[laharigandrapu11]

Fix --no-interactive still prompting for confirmation

Closes #1951

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What & Why

Running

 chat --no-interactive --trust-all-tools "<prompt>"

should execute automatically, but the model often responded with follow-up questions such as
“Would you like me to proceed?”. This broke scripted / CI usage.

Root cause: the model never knew the session was intended to be non-interactive.

Solution: inject a one-time system instruction at the very start of every --no-interactive session:
NOTE: This session is running with '--no-interactive'.
Do not ask for confirmation or additional input.
Proceed automatically, using any necessary tools, and output the final result.

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Implementation

• crates/chat-cli/src/cli/chat/mod.rs
  • When ChatArgs::no_interactive is true, prepend the constant NON_INTERACTIVE_INSTRUCTION
    to the first user prompt (or create an input if only stdin was provided).
  • Instruction is added once and does not affect later prompts.

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Testing

# style / lints
cargo +nightly fmt
cargo clippy --all-targets -- -D warnings

# full test suite
cargo test   # 216 passed

# manual check
cargo run --bin chat_cli -- login   # one-time auth

cargo run --bin chat_cli -- \
  chat --no-interactive --trust-all-tools \
  "Create a simple hello.txt file"

• Before patch: CLI asked for y/n confirmation.
• After patch: CLI executed fs_write immediately, created hello.txt, exited—no prompts.
• Behaviour without --no-interactive unchanged.

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Thank you for reviewing! 🙌