fix(sdk): validate task retry counts and timeout in decorator guardrails

[UGVicV]

Description

This PR resolves the issue where the @task decorator silently accepted negative retry counts and invalid timeout values, storing them in __task_config__ without validation. Schedulers could skip or repeat work based on invalid metadata.

Fix

• Added type validation for retries: rejects non-integer types (including bool) with TypeError.
• Added value validation for retries: rejects negative values with ValueError("retries must be non-negative").
• Added type validation for timeout: rejects non-integer types (including bool) with TypeError.
• Added value validation for timeout: rejects zero and negative values with ValueError("timeout must be a positive integer").
• Validation runs at decorator definition time (not at call time), catching errors early.
• Wrapped in try-except with logger.error() for robust error logging.
• Fixed pre-existing PEP8 violations (all lines under 79 characters).
• Removed unused imports (Any, Dict).

Verification (Proof)

Created new regression test file tests/test_sdk_decorators.py with 8 test cases:

• test_valid_retries: Valid retries=3 stored correctly.
• test_valid_zero_retries: Zero retries accepted.
• test_negative_retries: Negative retries raises ValueError.
• test_non_int_retries: String retries raises TypeError.
• test_bool_retries: Boolean retries raises TypeError.
• test_negative_timeout: Negative timeout raises ValueError.
• test_zero_timeout: Zero timeout raises ValueError.
• test_non_int_timeout: String timeout raises TypeError.

Test Execution Output

65 passed in 0.06s

Lint & Formatting Output

• flake8 src/sdk/decorators.py tests/test_sdk_decorators.py -> Passed (0 errors/warnings)
• git diff --check -> Passed (0 errors)

No secrets, tokens, or hidden context are included in the code.

Closes #2324.