Add MCP doctor for deterministic parameter resolution

[binrogithub]

Motivation

• Provide a deterministic way to resolve missing MCP parameters into explicit values using a simple, auditable algorithm.
• Prefer existing explicit context values, then user/vendor tagged defaults, and finally a stable tie-break among remaining candidates.
• Ensure resolution logic performs only read-only listing calls supplied by callers and returns both a ctx_patch and human-readable explanations.

Description

• Add package scaffolding with hc_agent and hc_agent/mcp and introduce hc_agent/mcp/doctor.py implementing the resolution logic.
• Implement Candidate and Resolution dataclasses to represent candidate items and resolution results.
• Add helper functions _coerce_candidate and _stable_key and the main API resolve_missing_parameters which takes ctx, missing, and list_calls and returns a Resolution.
• Add apply_ctx_patch to apply returned patches and use DEFAULT_TAGS (which can be overridden) to prefer tagged defaults before applying a stable tie-break.

Testing

• No automated tests were run for this change.

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Honor explicit empty default_tags override

When callers pass an empty set to default_tags to disable tagged-default preference, tags = default_tags or DEFAULT_TAGS treats the empty set as falsy and silently falls back to DEFAULT_TAGS. This makes it impossible to opt out of tagged defaults, and the resolution will still prefer tagged candidates even though the API suggests the override should be honored. Use an explicit if default_tags is None check so set() is respected.

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