docs: align MCP timeout wording with issue-148

[justrach]

Summary

• update README timeout wording to 10 minutes
• update website release copy to mention the longer timeout and stdin polling
• soften the src/mcp.zig comment so it matches the actual watchdog behavior

Notes

• stacked on top of timeout issue #148
• socials/ is gitignored in this repo, so that local note was not included in the PR

Refs #231

[github-actions]

Benchmark Regression Report

Threshold: 10.00%

Tool	Base (ns)	Head (ns)	Delta	Status
codedb_bundle	625252	633091	+1.25%	OK
codedb_changes	116001	113151	-2.46%	OK
codedb_deps	30954	30412	-1.75%	OK
codedb_edit	17426	16959	-2.68%	OK
codedb_hot	149721	147508	-1.48%	OK
codedb_outline	405906	444084	+9.41%	OK
codedb_read	168554	170093	+0.91%	OK
codedb_search	296547	298319	+0.60%	OK
codedb_snapshot	3501916	3490051	-0.34%	OK
codedb_status	30619	28501	-6.92%	OK
codedb_symbol	61424	62668	+2.03%	OK
codedb_tree	88081	93103	+5.70%	OK
codedb_word	91679	90784	-0.98%	OK