v0.12.0

Added

• "Your subscription" section in the HTML report: auto-detects Claude (plan + subscription start date) and Codex (ChatGPT plan + subscription start date) from the local OAuth account files. Only the plan name and start date are read — tokens, emails and other secrets are never touched. When sharing the report, the subscription date is masked together with the "Hide project names" toggle. Adds the subscription.py module and its tests.
• Project-share donut chart in the HTML report: pure-SVG (zero external deps) breakdown of token share per project; the top 6 projects get their own colour, the rest fold into "Other", and the centre shows the total.
• "Claude vs Codex" comparison section in the HTML report: surfaces the per-agent usage (tokens / share / cost) that build_report_data already computed but never displayed.

Fixed

• Double-counted report cost: build_report_data summed cost once over all entries and then recomputed it per entry inside the loop — effectively doubling the work on large datasets. Now accumulated once inside the loop.
• Duplicated clipboard code in the report's "copy command" button: the tip-copy button now reuses the shared copyText() helper instead of re-implementing the legacy-browser fallback.
• Hard-coded TWD rate: the USD→TWD estimate in the report is now a named _USD_TO_TWD constant with a note that it is a display estimate, not a live FX rate.