Add Teredo (RFC4380) embedding strategy

[zanbaldwin]

No description provided.

[greptile-apps]

Greptile Summary

This PR adds a new Teredo embedding strategy class implementing RFC 4380 §4, allowing the Multi version to extract and pack IPv4 addresses embedded in the 2001:0000::/32 (Teredo) prefix via XOR obfuscation of the last 4 bytes.

• Teredo::isEmbedded() accepts any address whose first 32 bits match 2001:0000:: (the full Teredo prefix range), and extract()/pack() correctly apply the 0xFFFFFFFF XOR mask; the deliberate asymmetry (non-canonical Teredo addresses decode to the canonical form when round-tripped) is clearly documented in the class PHPDoc.
• Test coverage includes extraction, packing, isEmbedded for both Teredo and non-Teredo 16-byte binaries, the well-known RFC 4380 worked example (192.0.2.45), and an integration test in MultiTest confirming that a Teredo address embedding 127.0.0.1 is classified as loopback.

Confidence Score: 4/5

Safe to merge; the implementation is correct and the XOR obfuscation follows RFC 4380 §4 exactly.

The Teredo strategy, test vectors (including the well-known RFC 4380 example), and Multi integration test are all correct. The only notable issue is a prose inconsistency in the documentation — the sentence still says "main three" after a fourth strategy was added to the table, and the deprecated strategy is not named. No production logic or test correctness is affected.

docs/05-strategies.md — the strategy-count and deprecation wording should be updated to match the four-entry table.

Important Files Changed

Filename	Overview
src/Strategy/Teredo.php	New Teredo embedding strategy; prefix check, XOR extraction, and canonical pack are all correct per RFC 4380 §4.
tests/DataProvider/Strategy/Teredo.php	Data provider with valid RFC 4380 test vectors, correct invalid-prefix sequences, and well-verified pack/extract pairs.
tests/Strategy/TeredoTest.php	Covers isEmbedded, extract, and pack for both valid Teredo inputs and length-invalid edge cases; test names and data providers are consistent.
tests/DataProvider/IpDataProviderInterface.php	Inserts TEREDO and LOOPBACK_TEREDO constants, shifting existing LOOPBACK_MAPPED/COMPATIBLE/DERIVED bit positions; low risk for test-only constants used symbolically.
docs/05-strategies.md	Table updated correctly, but the prose "main three (and one deprecated)" is inconsistent with a four-strategy table and doesn't identify which strategy is deprecated.

_{Reviews (1): Last reviewed commit: "feature(strategy): ✨ add Teredo (RFC4380..." | Re-trigger Greptile}

[greptile-apps]

The prose says "the main three (and one deprecated)" but the table now has four entries. The parenthetical also never identifies which strategy is deprecated (IPv4-compatible, per RFC 4291 §2.5.5.1). Consider updating the sentence to count accurately and name the deprecated strategy.

Suggested change

	for the main three (and one deprecated):
	for four strategies (the IPv4-compatible strategy is deprecated per RFC 4291):