Add CodeMash conference data

[hungud]

Summary

• Adds CodeMash to the conference data tracker.
• Uses current public CodeMash 2026 / Sessionize sources.
• Keeps conservative values where no public SEA or general speaker-fee commitment is available.

Sources / notes

• CodeMash FAQ: CodeMash Conference is incorporated as an Ohio non-profit / 501(c)(6), and organized by volunteers.
• CodeMash organizers page: current board and volunteer organizer context.
• Sessionize CodeMash 2026: event fee is free for speakers, accommodation expenses are covered, up to four hotel nights are covered, and limited travel assistance is available on a needs basis.
• I did not find a public commitment to sign the Speaker Engagement Agreement or a current general speaker-fee policy, so those fields are conservative per the issue guidance.

Validation

• Preserved the existing Markdown table schema and alphabetical placement.
• Local table check: each table row keeps 7 pipe characters / 6 data columns.

/claim #10

AI-assisted; reviewed before submission.