Add CodeMash conference data

[DevvoZA]

Summary

/claim #10

Adds CodeMash to the conference data tracker using public CodeMash sources while preserving the existing README table schema and alphabetical placement.

Source notes

• Conference homepage: https://codemash.org/
• Organizer/legal entity: https://codemash.org/faq/
• Speaker benefits: https://codemash.org/call-for-speakers-announcement/

Field notes

• Sign SEA?: No because I did not find a public statement that CodeMash signs the Speaker Engagement Agreement.
• Free Ticket?: Yes based on the published speaker benefits listing a four-day CodeMash pass.
• Reimburse Expenses?: Partial because the published speaker benefits list hotel room / housing-credit support, but not full travel and per diem reimbursement.
• Compensate Speakers?: PreCompilers because the speaker-benefits source describes a PreCompiler workshop honorarium.

Validation

• Markdown table pipe-count check: all rows have the expected column count.
• git diff --check -- README.md
• Source-link HTTP checks returned 200 for the CodeMash homepage, FAQ, and speaker-benefits page.

Demo note

This is a static README data update, so the PR diff is the review/demo surface.

[DevvoZA]

Demo video for this PR:

https://raw.githubusercontent.com/DevvoZA/conference-data/assets/codemash-demo-video/assets/codemash-demo.mp4

The video shows the CodeMash README row addition and validation results (table column count, git diff check, and source-link HTTP 200 checks).