Fix AgentState dunder keys (#84)

[pragati-0208]

Fix AgentState dunder keys

This PR fixes Issue #84 by removing double-underscore (__dunder__) keys from the AgentState TypedDict.

Changes

• __start_number__ → start_number
• __previous_text__ → previous_text
• Updated all references in the code.

These changes avoid potential conflicts with Python internal naming conventions and improve code clarity.

[pragati-0208]

Hi! This PR fixes Issue #84. Please let me know if any more changes are needed. Thanks!

[QuantumByte-01]

Critical bug — missing return statement in exception handler.

The return f"Error: {e}" is removed but no replacement is added:

except Exception as e:
    logger.error("Error in handle_chat: %s", e)
    logger.exception("Exception occurred in handle_chat")
    # ← no return here

handle_chat will return None on any exception. The API caller expects a str, so this will cause downstream errors on every exception path. Please add a return statement, e.g.:

    return "I encountered an error. Please try again."

---

Scope creep: This PR also replaces all print() calls with logging throughout agents.py — that is exactly what PR #85 does. Both PRs will conflict. Please limit this PR to only the dunder key renames (__start_number__ → start_number, __previous_text__ → previous_text) and fix the missing return. The logging cleanup should stay in PR #85.

[pragati-0208]

Thanks for the review!

• Added the missing return statement in the exception handler.
• Verified that this PR only includes the AgentState dunder key fixes (bug: AgentState uses __dunder__ keys which can clash with Python internals #84).
• No logging or unrelated changes are included.

Please let me know if anything else needs adjustment.

[QuantumByte-01]

Clean fix — exactly what was asked for. Dunder keys renamed correctly, return statement restored, no scope creep. Good to merge.