Chore/increase test coverage and add natspec

[alex0207s]

• fix the logic in LimitOrderSwap.sol to not allow zero takerToken orders or zero makerToken orders

• increase test coverage to near 100%; comment on the reasons why some branches cannot be covered.

• remove dead codes from the Tokenlon contracts.

• fix typos.

• add a script to package.json for generating coverage - coverage.

• add natspec to Tokenlon contracts.

[github-actions]

Changes to gas cost

Generated at commit: 58248155279e942d9175e334d673e4d9e9bff123, compared to commit: 019650b2eaf9c86d0e3fce3c04acfe001f5f4cd9

🧾 Summary (20% most significant diffs)

Contract	Method	Avg (+/-)	%
AllowanceTarget	spendFromUserTo unpause	+1,756 ❌ +2,113 ❌	+3.55% +9.02%

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Full diff report 👇

Contract	Deployment Cost (+/-)	Method	Min (+/-)	%	Avg (+/-)	%	Median (+/-)	%	Max (+/-)	%	# Calls (+/-)
AllowanceTarget	613,454 (0)	pause spendFromUserTo unpause	23,422 (0) 25,029 (0) 23,423 (0)	0.00% 0.00% 0.00%	26,608 (+354) 51,264 (+1,756) 25,536 (+2,113)	+1.35% +3.55% +9.02%	27,671 (0) 49,849 (+13,708) 25,536 (+2,113)	0.00% +37.93% +9.02%	27,671 (0) 91,606 (0) 27,649 (+4,226)	0.00% 0.00% +18.04%	4 (+1) 8 (+1) 2 (+1)

[github-actions]

Changes to gas cost

Generated at commit: 58248155279e942d9175e334d673e4d9e9bff123, compared to commit: 019650b2eaf9c86d0e3fce3c04acfe001f5f4cd9

🧾 Summary (20% most significant diffs)

Contract	Method	Avg (+/-)	%
LimitOrderSwap	fillLimitOrder fillLimitOrderGroup	-246,932 ✅ -68,112 ✅	-17.31% -28.05%

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Full diff report 👇

Contract	Deployment Cost (+/-)	Method	Min (+/-)	%	Avg (+/-)	%	Median (+/-)	%	Max (+/-)	%	# Calls (+/-)
LimitOrderSwap	2,730,640 (+36,206)	fillLimitOrder fillLimitOrderFullOrKill fillLimitOrderGroup	36,094 (0) 48,304 (+42) 31,168 (-166,968)	0.00% +0.09% -84.27%	1,179,473 (-246,932) 104,056 (+34) 174,739 (-68,112)	-17.31% +0.03% -28.05%	161,770 (-6,889) 48,304 (+42) 198,266 (-47,337)	-4.08% +0.09% -19.27%	29,534,880 (+1) 215,562 (+19) 291,975 (+195)	+0.00% +0.01% +0.07%	28 (+5) 3 (0) 9 (+3)
RFQ	2,465,421 (+21,622)	cancelRFQOffer feeCollector fillRFQ setFeeCollector	23,996 (+22) 382 (-44) 31,822 (0) 23,793 (+22)	+0.09% -10.33% 0.00% +0.09%	37,923 (+22) 382 (-44) 131,171 (+1,527) 25,964 (+22)	+0.06% -10.33% +1.18% +0.08%	38,918 (+22) 382 (-44) 147,976 (0) 23,998 (+22)	+0.06% -10.33% 0.00% +0.09%	49,859 (+22) 382 (-44) 238,908 (+15,387) 30,102 (+22)	+0.04% -10.33% +6.88% +0.07%	4 (0) 2 (+1) 24 (+2) 3 (0)
SmartOrderStrategy	1,226,691 (0)	approveTokens executeStrategy	56,282 (0) 23,234 (0)	0.00% 0.00%	185,084 (+10,734) 123,683 (+3,118)	+6.16% +2.59%	268,806 (0) 90,796 (+51,578)	0.00% +131.52%	268,806 (0) 610,220 (0)	0.00% 0.00%	33 (+6) 18 (+3)
CoordinatedTaker	2,367,349 (+1,248)	approveTokens submitLimitOrderFill	27,095 (0) 33,103 (0)	0.00% 0.00%	169,261 (+3,043) 128,473 (+9)	+1.83% +0.01%	189,038 (0) 70,073 (0)	0.00% 0.00%	189,038 (0) 256,667 (+19)	0.00% +0.01%	15 (+2) 7 (0)
GenericSwap	1,756,522 (+22,941)	executeSwap executeSwapWithSig	32,322 (+45) 39,528 (+44)	+0.14% +0.11%	117,670 (+45) 168,429 (+44)	+0.04% +0.03%	115,374 (+45) 175,155 (+44)	+0.04% +0.03%	252,012 (+45) 283,880 (+44)	+0.02% +0.02%	12 (0) 4 (0)