ENH: Add ZeroResp and ZeroResp v2 (tournament rev 2.2)

[Evreu1pro]

What

Adds two related adaptive long-memory strategies for the iterated Prisoner's Dilemma:

1. ZeroResp — epoch debt, stochastic retaliation buffer, systemic red line, anti-raider, finite-horizon harvest
2. ZeroResp v2 (implementation revision 2.2, tournament candidate) — same backbone plus:
   • Early sharp — delay=1 in the first turns (Prober-friendly)
   • Short adaptive buffer — mid-game delay 1–2 (responsive vs soft-majority / Downing-style play)
   • Echo-shield / contrition — ignore one mirror D after our queued strike
   • Noise-aware forgive — isolated mid-game noise after long mutual C (up to 2×)
   • Deadlock break — CD/DC loops force cooperative reset
   • Smart end-game harvest / grim probe — short remaining horizon only; cautious vs never-defectors

This PR supersedes #1495 (ZeroResp alone). Prefer reviewing this PR.

Why

ZeroResp v2.2 is the sandbox leader against classic Axelrod pools and exploiter heuristics while remaining non-cheating (inspects_source / manipulates_* all false).

External benchmarks (reproducible package)

Full report: https://github.com/Evreu1pro/ZeroResp

Setting	Result
Higher League Top-40 · 400×2 · 7 seeds	avg rank #2 (avg/r ≈ 2.760); best seed #1
Endurance Top-40 · 1501 turns · 5 seeds	stable #2–#3 (avg rank 2.40)
H2H vs Omega TFT · 1000 / 5000 turns	mutual coop ~99.7–99.9%; near-parity scores
Survival elimination to Top-5	#1 every round, final avg/r ≈ 3.000
Channel noise 1–3%	known weaker regime vs Omega TFT (documented honestly)

How to test

pytest axelrod/tests/strategies/test_zeroresp.py axelrod/tests/strategies/test_zeroresp_v2.py -q

Smoke:

import axelrod as axl
m = axl.Match((axl.ZeroRespV2(), axl.TitForTat()), turns=100, seed=0)
m.play()
print(m.final_score())

Coverage

• Initial move always C
• Early sharp delay=1
• Echo shield, noise forgive, deadlock break
• Systemic red line, anti-raider, smart harvest
• reset() / clone for multi-rep tournaments
• Match-length edge cases

Changes

Path	Role
axelrod/strategies/zeroresp.py	ZeroResp
axelrod/strategies/zeroresp_v2.py	ZeroResp v2 (rev 2.2)
axelrod/tests/strategies/test_zeroresp*.py	TestPlayer suites
_strategies.py / classifiers / docs	registration

Also includes CI hardening (numpy<2, black formatting) so the suite stays green on current runners.

Breaking

No — additive only.

Review notes for maintainers

• Happy to drop ZeroResp (v1) and keep only ZeroResp v2 if you prefer a single strategy.
• Happy to rename the display string to ZeroResp v2.2 if that is clearer in plots.
• Showcase + CSV aggregates: https://github.com/Evreu1pro/ZeroResp

[Evreu1pro]

Update for maintainers (2026-08-04)

Pushed revision 2.2 of ZeroResp v2 (short adaptive buffer, dual noise-aware forgiveness, smart harvest / grim probe).

CI was already green on the previous commit; this push should re-run the matrix.

Evidence package (algorithm + unit tests + Higher League / deep-validation tables):
https://github.com/Evreu1pro/ZeroResp

Why this is ready for the strategy list

• Non-cheating classifiers (no source/state manipulation)
• Full TestPlayer suite + registration + docs automodule
• Stable elite placement (Added docstring to Grudger's strategy method #1–Get results graph to plot but sort strategies by median score #3) vs classic + Axelrod elites; H2H with Omega TFT stays near-ideal mutual cooperation
• Honest limitation documented: sustained 1–3% channel noise

Request: please review when you have bandwidth. If two strategies are too many, I can collapse to a single ZeroResp entry with the 2.2 logic.

Thank you for maintaining Axelrod — happy to address any requested API/doc changes promptly.

[Evreu1pro]

CI fix for revision 2.2 (just pushed)

Addressed the two failures from the previous matrix run:

1. test_repr — Player.__repr__ appends base_epoch, so the TestPlayer name is now ZeroResp v2: 25 (was ZeroResp v2).
2. Coverage 99.95% — added targeted tests for smart harvest / grim-probe paths (last-safe D, probe_fired, stochastic probe, non-grim probe window).

What is in this PR (for clarity):

• ZeroResp — v1 backbone
• ZeroResp v2 — class API, implementation revision 2.2 (short adaptive buffer, dual noise forgive, smart harvest / grim probe)

Happy to rename the display string to ZeroResp v2.2 if maintainers prefer that in tournament plots.

[drvinceknight]

Can you fix the merge conflicts (#1497 fixed a problem with numpy).

[Evreu1pro]

Thanks @drvinceknight — merge conflicts with dev are resolved.

Took numpy>=2.1 from #1497 and kept the float() cast in fingerprint point generation. CI should re-run on this push.