research: finite LE semantic evaluator with replayable C2 evidence

[mountain]

Closes #144.

Outcome

EXPAND within the frozen finite LE fragment. This PR upgrades the carrier compiler's syntax-level C2 classification into exact, replayable semantics for a bounded real single-exponential rational-rate task family.

Implemented:

• strict finite expression DAG and rational-rate chart derivation t = exp(-N/q) -> 0+;
• finite Laurent/Taylor normal form with exact result and residual;
• conservative real-domain witnesses and typed fail-closed/resource failures;
• deterministic replay of chart, result, residual, branches, costs, digests, and exactly three C2 obligations;
• public controls, same-information SymPy baseline, commit–reveal held-out, and seconds-scale default CI bridge.

Commit–reveal

• preimplementation commitment: eedef97f8071ea3da687a805b7ea3e8385aa49c0829f2c962a3c6bc8ec181655
• remote source freeze: 5df657d450233e14fa6d77a1efb5be36d6bc02e6
• held-out result: derived q=3, exact 1/5, normal form 1/5 - t/6 + O(t**2), cancellation jump 4, valid 69-step replay
• no post-reveal grammar, budget, or scoring change

Verification

• workstream: 18 passed
• default CI bridge: 2 passed
• post-reveal manifest: verified
• compiler/replay path: no generic sympy.limit

Claim boundary

The same-information SymPy baseline also computes every numerical answer. The software gain is explicit semantics and replayable C2 discharge, not a raw computability/speed advantage. Surreal numbers play no substantive runtime role here. No general LE/transseries/hyperseries/surreal, symbolic-height, arbitrary nesting, complexity, Core, Theory Map, or Public API claim is made.

[mountain]

Source freeze complete

The evaluator implementation is now remotely frozen at 5df657d450233e14fa6d77a1efb5be36d6bc02e6 (tree dc5d1d292952423984cbba6fc240aaedd8996bde).

Pre-reveal checks:

• nested workstream: 15 passed
• default CI bridge: 2 passed
• manifest: verified
• compiler/replay path contains no generic sympy.limit call

The preimplementation held-out commitment remains eedef97f8071ea3da687a805b7ea3e8385aa49c0829f2c962a3c6bc8ec181655. The reveal gate is now open. This is explicitly a self-commit/reveal check, not independent-agent evidence.

[mountain]

Held-out reveal complete

• commitment verified by canonical JSON hashing
• no post-reveal grammar, budget, or scoring change
• derived chart: t=exp(-N/3)->0+
• result: exact 1/5
• finite normal form: 1/5 - t/6 + O(t**2)
• cancellation jump: 4
• certificate: 1182 bytes
• replay: valid in 69 steps
• same-information SymPy baseline: 1/5 (no certificate/replay credit)

Local verification is green: 18 workstream tests, 2 default CI bridge tests, and the post-reveal manifest. Disposition: EXPAND within the exact frozen fragment, with no broader surreal/transseries claim.

[mountain]

CI #1809 is green: Python 3.10 and 3.14 compatibility jobs passed; the Python 3.12 full-test-and-build job passed. The research gate is complete and the PR is being marked ready for review.