docs: remove links to deleted OAuth examples; fix migration-guide cross-references

[ZayanKhan-12]

Three commits:

1. packages/oauth/README.md — the Examples section links ../../examples/oauth-v2 and ../../examples/oauth-v1, but those example apps were removed from the repository (only openid-connect and socket-mode remain), so both links 404. Removed the dead section.
2. docs/english/oauth.md — the same two examples linked as absolute GitHub URLs; both curl 404 (the parent examples/ tree is 200). Removed.
3. Migration guides — the web-api v8 guide's requestInterceptor cross-reference was missing the # and used a slug matching no heading (now points at the real #weve-removed-the-requestinterceptor-and-requestinterceptor-types anchor, heading present in the same file), and the socket-mode v3 guide linked ./web-api-v8-migration.md, which doesn't exist anywhere (now ../web-api/migrating-web-api-package-to-v8.md).

Verification: all dead targets confirmed missing (tree + curl), all corrected targets confirmed present; root npm run build and the touched package's suite (npm test --workspace=packages/oauth) pass locally — 16/16 tests (Node 22, macOS arm64).

Prepared with AI assistance (Claude).

[changeset-bot]

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Latest commit: a335bb5

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[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @zk-khan to sign the Salesforce Inc. Contributor License Agreement.

[WilliamBergamin]

Thanks for this fix 💯

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.25%. Comparing base (046647f) to head (a335bb5).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2679      +/-   ##
==========================================
+ Coverage   89.11%   89.25%   +0.13%     
==========================================
  Files          65       65              
  Lines       10339    10339              
  Branches      471      471              
==========================================
+ Hits         9214     9228      +14     
+ Misses       1095     1084      -11     
+ Partials       30       27       -3     

Flag	Coverage Δ
cli-hooks	89.11% <ø> (ø)
cli-test	89.11% <ø> (ø)
logger	89.11% <ø> (ø)
oauth	89.11% <ø> (ø)
socket-mode	89.11% <ø> (ø)
web-api	89.11% <ø> (ø)
webhook	89.11% <ø> (ø)

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[lukegalbraithrussell]

Docs changes are good! Thank you!

[WilliamBergamin]

@ZayanKhan-12 these changes are ready to merge 🚀 but I'm unable to merge this until you've signed the CLA