Attribution emoji in source comments violates the no-emoji rule

[n24q02m]

Recording only — no fix requested for now.

The house style forbids emoji in code and technical documentation. Eight
occurrences remain on main, measured with git grep over packages/:

Seven are ⚡ Bolt: attribution markers on optimisation comments:

File	Line
packages/core-py/src/mcp_core/auth/local_oauth_app.py	205
packages/core-py/src/mcp_core/auth/delegated_oauth_app.py	257
packages/core-py/src/mcp_core/storage/d1.py	93, 102
packages/core-ts/src/auth/local-oauth-app.ts	841, 922
packages/core-ts/src/auth/delegated-oauth-app.ts	881

The eighth is different in kind — packages/core-ts/tests/auth/cookie-parsing-bench.test.ts:6
is prose referring to the marker rather than carrying one, so removing the
markers above would leave that sentence dangling. Fix both together or neither.

The comments themselves are useful (they explain why a hot path avoids an
allocation); only the emoji prefix is at issue. The mechanical fix is to drop
the ⚡ Bolt: prefix and keep the explanation. Reproduce with:

git grep -nP '[\x{1F300}-\x{1FAFF}\x{2600}-\x{27BF}\x{2B00}-\x{2BFF}]' -- packages/

Worth pairing with a lint rule so the class cannot come back, rather than a
one-off sweep.