[March-7]

Fully specializing a reusable AtomicAgent subclass can leave a TypeVar in input_schema or output_schema, causing run() to fail before sending a completion request. Resolve the concrete bindings along the instance's specialized bases instead of caching raw type parameters on the class. Direct agents, concrete subclasses and untyped defaults keep their behavior, and different specializations keep independent bindings.

This extends the concrete-subclass handling in #187 to generic intermediate classes.

Validation:

• New native regressions: 7 failed / 5 passed on the base; the same test bytes pass all 12 cases with the fix.
• Independent local HTTP probe: 8/8 cases pass, including reordered parameters, forwarded templates and two output specializations.
• Core suite: 818 passed, 3 live MiniMax tests skipped.
• Repository Black and Flake8 checks pass; the configured Pyright check reports 0 errors. An additional direct source scan reports 18 existing diagnostics versus 21 on the base, with none added.

Prepared with AI assistance.

[Eigenwise]

Rechecked a800ffa. All twelve native generic-schema tests pass locally. Independent offline probes covered intermediate and reordered generic bindings, specialization independence, public schema overrides, and the hook-lifecycle change. No public-API blocker found. Exact-head CI is green.